File sizes for "iPod High" preset

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Se7enLC
Posts: 9
Joined: Wed Jan 09, 2008 6:41 pm

File sizes for "iPod High" preset

Post by Se7enLC »

I wrote a little script to encode DVDs for my ipod using the high-quality iPod preset. The DVDs seem to come out around 1.3 to 1.5 gigs encoded. This seems really high to me (I was expecting more like 600mb). Here's the command I'm using (consistent with the high-quality ipod preset):

Code: Select all

/usr/local/bin/HandBrakeCLI -e x264b30 -b 700 -B 160 -R 48 -E faac -f mp4 -w 320 -x keyint=300:keyint-min=30:bframes=0:cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:subme=6:no-fast-pskip=1 -m -t 1 -i /dev/dvd -o movie.mp4
Anyone else try something similar or get similar results?
rhester
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Post by rhester »

That is very high - what I'd expect for a high-res/1500kbps rip. What does iTunes report the bitrate as?

Rodney
Se7enLC
Posts: 9
Joined: Wed Jan 09, 2008 6:41 pm

Post by Se7enLC »

iTunes? What's that?

Code: Select all

[jeff@djali movies]$ midentify Firefly-1.mp4
ID_VIDEO_ID=0
ID_AUDIO_ID=1
ID_SUBTITLE_ID=2
ID_FILENAME=Firefly-1.mp4
ID_DEMUXER=mov
ID_VIDEO_FORMAT=avc1
ID_VIDEO_BITRATE=0
ID_VIDEO_WIDTH=640
ID_VIDEO_HEIGHT=368
ID_VIDEO_FPS=23.988
ID_VIDEO_ASPECT=0.0000
ID_AUDIO_FORMAT=mp4a
ID_AUDIO_BITRATE=159984
ID_AUDIO_RATE=48000
ID_AUDIO_NCH=2
ID_LENGTH=5198.99
ID_VIDEO_CODEC=ffh264
ID_AUDIO_BITRATE=159984
ID_AUDIO_RATE=48000
ID_AUDIO_NCH=2
ID_AUDIO_CODEC=faad
rhester
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Post by rhester »

Give me either a) the output from AVInaptic (preferably) or b) the output from "mp4box -info", now that I get what's going on. ;) A bitrate of "0" is not helpful. <G>

Rodney
Se7enLC
Posts: 9
Joined: Wed Jan 09, 2008 6:41 pm

Post by Se7enLC »

Here's the output of MP4Box:

Code: Select all

* Movie Info *
        Timescale 48000 - Duration 01:26:38.985
        Fragmented File no - 3 track(s)
        File Brand mp42 - version 0
        Created: GMT Wed Jan  9 06:21:58 2008

File has root IOD
Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
Visual PL: ISO Reserved Profile (0x7f)
Audio PL: High Quality Audio Profile @ Level 2 (0x0f)
No streams included in root OD

Track # 1 Info - TrackID 1 - TimeScale 48000 - Duration 01:26:38.985
Media Info: Language "Undetermined" - Type "vide" - Sub Type "avc1" - 124651 samples
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
AVC/H264 Video - Visual Size 640 x 368 - Profile Baseline @ Level 3
Self-synchronized

Track # 2 Info - TrackID 2 - TimeScale 48000 - Duration 01:26:38.890
Media Info: Language "English" - Type "soun" - Sub Type "mp4a" - 243698 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 48000
Synchronized on stream 1

Track # 3 Info - TrackID 3 - TimeScale 48000 - Duration 01:26:38.985
Media Info: Language "Undetermined" - Type "text" - Sub Type "text" - 20 samples
3GPP/MPEG-4 Timed Text - Size 0 x 0 - Translation X=0 Y=0 - Layer 0
Haven't heard of avinaptic, but I'll look around for it. I just used the ipodhigh preset from http://trac.handbrake.fr/wiki/BuiltInPresets, so I didn't do anything out of the ordinary. Anybody else who used that preset (or the options I listed above) would end up with the same file.

As a comparison, I used these options and got a 300mb file (for a 45 minute show that was 500mb using the above method). It encodes much faster (40fps vs 6-8fps for h264)

Code: Select all

-b 1025 -B 128 -R 48 -E faac -f mp4 -m
rhester
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Post by rhester »

Shoot - "mp4box -info 1", please.

AVInaptic is Googlable and is about the best H.264 problem analysis tool on the planet.

Rodney
jbrjake
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Post by jbrjake »

File sizes for "iPod High" preset
using the high-quality iPod preset
the command I'm using (consistent with the high-quality ipod preset)
I just used the ipodhigh preset
I'm rather confused -- you keep on saying you used the iPod High-Rez preset but your command line shows the iPod Low-Rez preset....
Se7enLC
Posts: 9
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Re: File sizes for "iPod High" preset

Post by Se7enLC »

Sorry for the delay. I was on vacation and when I got back, my cpu had burned out (literally). I'm on a new machine now, but I still have the same files. I will double-check the settings used to encode, but judging by the resolution (640 width), this must be the high-rez output.

Code: Select all

djali backups # MP4Box -info 1 Firefly-1.mp4
Track # 1 Info - TrackID 1 - TimeScale 48000 - Duration 01:26:38.985
Media Info: Language "Undetermined" - Type "vide" - Sub Type "avc1" - 124651 samples
Handler name:
MPEG-4 Config
        Visual Stream - ObjectTypeIndication 0x21
        AVC/H264 Video - Visual Size 640 x 368 - Profile Baseline @ Level 3
        Decoding Buffer size 0 - Average bitrate 0 kbps - Max Bitrate 0 kbps
        No stream dependencies for decoding
        StreamPriority 0

Computed info from media:
        Total size 965827562 bytes - Total samples duration 5198944 ms
        Average rate 644 kbps - Max Rate 3011 kbps
From the handbrake wrapper script I wrote:

Code: Select all

iPod High Res:
preset_options="-e x264b30 -b 1500 -B 160 -R 48 -E faac -f mp4 -w 640 -x keyint=300:keyint-min=30:bframes=0:cabac=0:ref=1:vbv-maxrate=1500:vbv-bufsize=2000:analyse=all:me=umh:subme=6:no-fast-pskip=1 -m"

iPod Mpeg4:
preset_options="-b 1025 -B 128 -R 48 -E faac -f mp4 -m"

iPod Low-Res
preset_options="-e x264b30 -b 700 -B 160 -R 48 -E faac -f mp4 -w 320 -x keyint=300:keyint-min=30:bframes=0:cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:subme=6:no-fast-pskip=1 -m"
Looks like I posted the wrong command-line before. Above are the correct options it used. In either case, neither the high or low-res video should result in a 1 gig file:
jbrjake
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Re: File sizes for "iPod High" preset

Post by jbrjake »

Se7enLC wrote:Looks like I posted the wrong command-line before.
...which nullifies pretty much every bit of advice you were given above.
In either case, neither the high or low-res video should result in a 1 gig file:
Um...why shouldn't the high-rez preset, which uses a video bitrate of 1500 and an audio bitrate of 160, result in a 1 gig file when encoding a source with a duration of an hour and 20+ minutes? Isn't that just arithmetic?
Se7enLC
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Re: File sizes for "iPod High" preset

Post by Se7enLC »

That's what I was asking. It seemed a bit strange to have an h264 copy of a DVD be 1.5 gigs, while a divx copy of the movie is 700mb. I was just checking to see if I missed something.

What was really strange is that using the standard mpeg4 encoding was faster to encode AND came out significantly smaller in size. I thought h264 was meant to be the bees-knees when it comes to encoding things to be small but high-quality. Is it somehow upsidedown when the resolution is larger than 320x200?
nightstrm
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Re: File sizes for "iPod High" preset

Post by nightstrm »

Se7enLC wrote:That's what I was asking. It seemed a bit strange to have an h264 copy of a DVD be 1.5 gigs, while a divx copy of the movie is 700mb. I was just checking to see if I missed something.

What was really strange is that using the standard mpeg4 encoding was faster to encode AND came out significantly smaller in size. I thought h264 was meant to be the bees-knees when it comes to encoding things to be small but high-quality. Is it somehow upsidedown when the resolution is larger than 320x200?
At the same bitrates, the files will be similar in size (that's math). In a one-sentence over simplification, H.264 allows you to use lower bitrates and achieve the same quality.
jbrjake
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Re: File sizes for "iPod High" preset

Post by jbrjake »

Se7enLC wrote:Is it somehow upsidedown when the resolution is larger than 320x200?
Resolution has, what, exactly, to do with file size?

I don't understand how I can be any clearer than I am in the documentation:
The size of a video is the bitrate times the length.
Se7enLC
Posts: 9
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Re: File sizes for "iPod High" preset

Post by Se7enLC »

Resolution has, what, exactly, to do with file size?
Resolution could quite easily effect how well a compression algorithm works (like how selecting a non power-of-2 makes FFT algorithms slow). That's not the case here, though.

I just wanted to know if a 1.5 gig file was reasonable for an average dvd encoded using the ipod high-res preset, and I guess that is a yes? I didn't realize file size was really as simple as bitrate x length. I somehow was assuming framerate, audio quality, resolution, etc came into play there.

Seeing as I didn't notice any difference between the MPEG4 default and the h264 ipod high res video, I will play around with the settings and come up with a new preset that makes more sense for my purposes. Thanks for clarifying.
Polygon
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Re: File sizes for "iPod High" preset

Post by Polygon »

jbrjake wrote:
I don't understand how I can be any clearer than I am in the documentation:
The size of a video is the bitrate times the length.
that can't be right.

so your saying that a 300x200 resolution video, and a 600x400 resolution video , of the exact same length and bitrate, are the same size? Resolution, and audio quality must play some factor in filesize.
nightstrm
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Re: File sizes for "iPod High" preset

Post by nightstrm »

Yep, that's math. A bit is a bit no matter how you look at it.

Note, we are talking about total bitrate (audio + video), so yes audio quality plays a part but won't have a noticeable impact as long as the same bitrate is used in both encodes.
Polygon
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Re: File sizes for "iPod High" preset

Post by Polygon »

as a test to see if this was really the case, i encoded a chapter of a dvd with only changing the resolution of the video.
mark@Cactus-Fantastico:~$ HandBrakeCLI -i /media/LinuxBackup/vobcopy/BOURNE_SUPREMACY/VIDEO_TS/ -o /media/LinuxBackup/movie_normal.mp4 -t 2
was the normal command
mark@Cactus-Fantastico:~$ HandBrakeCLI -i /media/LinuxBackup/vobcopy/BOURNE_SUPREMACY/VIDEO_TS/ -o /media/LinuxBackup/movie_half.mp4 -t 2 -w 320 -l 240
was the second command, with the resolution cut in half.

and here are the results:

Image

Image

Whats really strange is the smaller res video is almost twice as big, but im guessing that is something to do with the aspect ratio not being the same, but two different resolutions, two different file sizes. Unless I am missing something, I fail to see how the size of a video is just the bitrate times the length.
rhester
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Re: File sizes for "iPod High" preset

Post by rhester »

Urm...because the unit of measure is bits-per-second?

See http://forum.handbrake.fr/viewtopic.php?f=14&t=3920 - you aren't the only one who found this unintuitive.

But it really doesn't bear discussion, because it is the correct and only answer, and isn't negotiable. It's math. Resolution has not one single thing to do with it, and while audio bitrate does, it's negligible (and also utterly irrelevant in terms of video bitrate).

Rodney
Polygon
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Re: File sizes for "iPod High" preset

Post by Polygon »

that makes sense. Thanks for sharing that. So if you have a smaller res video, you can have a smaller bitrate and therefore smaller size and have it look as good as if it had a high bitrate...but in a larger res, you need higher bitrate in order for the quality to not look like crap.

i feel like ive learned something today =P
Se7enLC
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Re: File sizes for "iPod High" preset

Post by Se7enLC »

Polygon wrote:as a test to see if this was really the case, i encoded a chapter of a dvd with only changing the resolution of the video.

<clip>

Whats really strange is the smaller res video is almost twice as big, but im guessing that is something to do with the aspect ratio not being the same, but two different resolutions, two different file sizes. Unless I am missing something, I fail to see how the size of a video is just the bitrate times the length.
I see how the video size is bitrate x length, but you bring up an interesting point. Why is the 320x240 video used as the example twice the filesize of the 640x480 video? A lower resolution video should have a LOWER bitrate requirement to achieve the same quality as a high-resolution video, and therefore should be a lower overall file size. Since the bitrate wasn't manually changed, we can guess that maybe it's using the same bitrate for both. If that's the case, shouldn't they be the SAME filesize?

The only things I can come up with that make sense:
- Handbrake is selecting bitrates for you, and doing it backwards (ie, higher rates for smaller sizes)
- Perhaps using too high a bitrate for a small resolution video results in poor compression rates? (doesn't make sense if we assume the static filesize of bitrate x video length)
jbrjake
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Re: File sizes for "iPod High" preset

Post by jbrjake »

You people are insane.

A bit is a bit is a bit is a bit is a bit is a bit is a bit!

You can do an encode at a width of 320 or at a full anamorphic width, but as long as you use the same bitrate they will be pretty much the same size, except for minor fluctuations in container overhead.

Code: Select all

Khaybet:hb-conan jonr$ ./HandBrakeCLI -i ~/Movies/DVD_VIDEO -c 8 -e x264 -w 320 -b 1000 -v -o /Volumes/MyBook/small.mp4 ; ./HandBrakeCLI -i ~/Movies/DVD_VIDEO -c 8 -p -b 1000 -v -o /Volumes/MyBook/big.mp4 -e x264
[11:31:49] hb_init: checking cpu count
[11:31:49] hb_init: starting libhb thread
[11:31:49] thread f0081000 started ("libhb")
HandBrake 0.9.1 (2007100800) - http://handbrake.m0k.org/
2 CPUs detected
Opening /Users/jonr/Movies/DVD_VIDEO...
[11:31:49] hb_scan: path=/Users/jonr/Movies/DVD_VIDEO, title_index=1
[11:31:49] thread f0103000 started ("scan")
[11:31:49] scan: trying to open with libdvdread
[11:31:49] scan: DVD has 5 title(s)
[11:31:49] scan: scanning title 1
[11:31:49] scan: opening IFO for VTS 2
[11:31:49] pgc_id: 1, pgn: 1: pgc: 0x7018d0
[11:31:49] scan: vts=2, ttn=1, cells=0->24, blocks=0->3318433, 3318434 blocks
[11:31:49] scan: duration is 01:58:25 (7105000 ms)
[11:31:49] scan: checking audio 1
[11:31:49] scan: id=80bd, lang=English (AC3), 3cc=eng
[11:31:49] scan: checking audio 2
[11:31:49] scan: id=81bd, lang=English (AC3), 3cc=eng
[11:31:49] scan: checking audio 3
[11:31:49] scan: id=82bd, lang=English (AC3), 3cc=eng
[11:31:49] scan: checking audio 4
[11:31:49] scan: id=83bd, lang=English (AC3), 3cc=eng
[11:31:49] scan: checking audio 5
[11:31:49] scan: id=84bd, lang=English (AC3), 3cc=eng
[11:31:49] scan: checking audio 6
[11:31:49] scan: id=8dbd, lang=English (DTS), 3cc=eng
[11:31:49] scan: checking subtitle 1
[11:31:49] scan: id=21bd, lang=English, 3cc=eng
[11:31:49] scan: title 1 has 23 chapters
[11:31:49] scan: chap 1 c=0->1, b=0->166678 (166679), 362603 ms
[11:31:49] scan: chap 2 c=2->2, b=166679->413695 (247017), 507416 ms
[11:31:49] scan: chap 3 c=3->3, b=413696->640900 (227205), 497450 ms
[11:31:49] scan: chap 4 c=4->4, b=640901->770821 (129921), 283532 ms
[11:31:49] scan: chap 5 c=5->5, b=770822->883743 (112922), 238361 ms
[11:31:49] scan: chap 6 c=6->6, b=883744->1119528 (235785), 453404 ms
[11:31:49] scan: chap 7 c=7->7, b=1119529->1274496 (154968), 343424 ms
[11:31:49] scan: chap 8 c=8->8, b=1274497->1309749 (35253), 74260 ms
[11:31:49] scan: chap 9 c=9->9, b=1309750->1476110 (166361), 390453 ms
[11:31:49] scan: chap 10 c=10->10, b=1476111->1607446 (131336), 278404 ms
[11:31:49] scan: chap 11 c=11->11, b=1607447->1723796 (116350), 260323 ms
[11:31:49] scan: chap 12 c=12->13, b=1723797->1913499 (189703), 406573 ms
[11:31:49] scan: chap 13 c=14->14, b=1913500->2041986 (128487), 259278 ms
[11:31:49] scan: chap 14 c=15->15, b=2041987->2245830 (203844), 427450 ms
[11:31:49] scan: chap 15 c=16->16, b=2245831->2359338 (113508), 247468 ms
[11:31:49] scan: chap 16 c=17->17, b=2359339->2499502 (140164), 302414 ms
[11:31:49] scan: chap 17 c=18->18, b=2499503->2611539 (112037), 256230 ms
[11:31:49] scan: chap 18 c=19->19, b=2611540->2749521 (137982), 297476 ms
[11:31:49] scan: chap 19 c=20->20, b=2749522->2847022 (97501), 189421 ms
[11:31:49] scan: chap 20 c=21->21, b=2847023->3002376 (155354), 351454 ms
[11:31:49] scan: chap 21 c=22->22, b=3002377->3097643 (95267), 194169 ms
[11:31:49] scan: chap 22 c=23->23, b=3097644->3318246 (220603), 482415 ms
[11:31:49] scan: chap 23 c=24->24, b=3318247->3318433 (187), 1010 ms
[11:31:49] scan: aspect = 16
[11:31:49] scan: decoding previews for title 1
[11:31:49] scan: preview 1
[11:31:49] scan: AC3, rate=48000Hz, bitrate=192000
[11:31:49] scan: AC3, rate=48000Hz, bitrate=192000
[11:31:49] scan: AC3, rate=48000Hz, bitrate=192000
[11:31:49] scan: AC3, rate=48000Hz, bitrate=192000
[11:31:49] scan: checking for DCA syncinfo
[11:31:49] scan: DCA, rate=48000Hz, bitrate=768000
[11:31:49] scan: AC3, rate=48000Hz, bitrate=448000
[11:31:49] scan: preview 2
[11:31:49] scan: preview 3
[11:31:49] scan: preview 4
[11:31:49] scan: preview 5
[11:31:49] scan: preview 6
[11:31:49] Title's mostly progressive NTSC, setting fps to 23.976
[11:31:49] scan: preview 7
[11:31:49] scan: preview 8
[11:31:49] scan: preview 9
Scanning title 1...
[11:31:49] scan: preview 10
[11:31:49] scan: 720x480, 23.976 fps, autocrop = 54/60/6/4
[11:31:49] scan: title (0) job->width:704, job->height:304
[11:31:49] thread f0103000 exited ("scan")
[11:31:49] thread f0103000 joined ("scan")
[11:31:49] libhb: scan thread found 1 valid title(s)
+ title 1:
  + vts 2, ttn 1, cells 0->24 (3318434 blocks)
  + duration: 01:58:25
  + size: 720x480, aspect: 1.78, 23.976 fps
  + autocrop: 54/60/6/4
  + chapters:
    + 1: cells 0->1, 166679 blocks, duration 00:06:03
    + 2: cells 2->2, 247017 blocks, duration 00:08:27
    + 3: cells 3->3, 227205 blocks, duration 00:08:17
    + 4: cells 4->4, 129921 blocks, duration 00:04:44
    + 5: cells 5->5, 112922 blocks, duration 00:03:58
    + 6: cells 6->6, 235785 blocks, duration 00:07:33
    + 7: cells 7->7, 154968 blocks, duration 00:05:43
    + 8: cells 8->8, 35253 blocks, duration 00:01:14
    + 9: cells 9->9, 166361 blocks, duration 00:06:30
    + 10: cells 10->10, 131336 blocks, duration 00:04:38
    + 11: cells 11->11, 116350 blocks, duration 00:04:20
    + 12: cells 12->13, 189703 blocks, duration 00:06:47
    + 13: cells 14->14, 128487 blocks, duration 00:04:19
    + 14: cells 15->15, 203844 blocks, duration 00:07:07
    + 15: cells 16->16, 113508 blocks, duration 00:04:07
    + 16: cells 17->17, 140164 blocks, duration 00:05:02
    + 17: cells 18->18, 112037 blocks, duration 00:04:16
    + 18: cells 19->19, 137982 blocks, duration 00:04:57
    + 19: cells 20->20, 97501 blocks, duration 00:03:09
    + 20: cells 21->21, 155354 blocks, duration 00:05:51
    + 21: cells 22->22, 95267 blocks, duration 00:03:14
    + 22: cells 23->23, 220603 blocks, duration 00:08:02
    + 23: cells 24->24, 187 blocks, duration 00:00:01
  + audio tracks:
    + 1, English (AC3) (Dolby Surround), 48000Hz, 192000bps
    + 2, English (AC3) (5.1 ch), 48000Hz, 448000bps
    + 3, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 4, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 5, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 6, English (DTS) (5.1 ch), 48000Hz, 768000bps
  + subtitle tracks:
    + 1, English (iso639-2: eng)
[11:31:49] thread f0103000 started ("work")
[11:31:49] 1 job(s) to process
[11:31:49] starting job
[11:31:49]  + device /Users/jonr/Movies/DVD_VIDEO
[11:31:49]  + title 1, chapter(s) 8 to 8
[11:31:49]  + 720x480 -> 320x144, crop 54/60/6/4
[11:31:49]  + filters
[11:31:49]  + 23.976 fps, video bitrate 1000 kbps, pass 0
[11:31:49]  + PixelRatio: 0, width:320, height: 144
[11:31:49]  + encoder x264
[11:31:49]  + audio 128 kbps, 44100 Hz
[11:31:49]  + encoder faac
[11:31:49]    + 80bd, English (AC3) (Dolby Surround)
[11:31:49]      + Requested mixdown: Dolby Pro Logic II (HB_AMIXDOWN_DOLBYPLII)
[11:31:49]      + Actual mixdown: Dolby Surround (HB_AMIXDOWN_DOLBY)
[11:31:49] thread f0185000 started ("reader")
[11:31:49]  + output: /Volumes/MyBook/small.mp4
[11:31:49] thread f0207000 started ("muxer")
[11:31:49] thread f0289000 started ("MPEG-2 decoder (libmpeg2)")
[11:31:49] thread f030b000 started ("Renderer")
[11:31:49] dvd: Beginning of Cell (8) at block 1274497
Encoding: task 1 of 1, 0.00 %[11:31:50] encx264: keyint-min: 24, keyint-max: 240
[11:31:50] encx264: opening libx264 (pass 0)
x264 [info]: using cpu capabilities: Altivec 
[11:31:50] thread f038d000 started ("H.264/AVC encoder (libx264)")
No accelerated IMDCT transform found
[11:31:50] thread f040f000 started ("AC3 decoder")
[11:31:50] a52_syncinfo failed
[11:31:50] a52_syncinfo ok
[11:31:50] thread f0491000 started ("AAC encoder (libfaac)")
[11:31:50] sync: expecting 1804 video frames
[11:31:50] sync: first pts is 241979469
Encoding: task 1 of 1, 88.19 % (67.88 fps, avg 75.19 fps, ETA 00h00m03s)[11:32:11] dvd: End of Cell (8) at block 1309344
Encoding: task 1 of 1, 90.02 % (67.88 fps, avg 75.19 fps, ETA 00h00m03s)[11:32:11] dvd: Beginning of Cell (9) at block 1309750
[11:32:11] dvd: Chapter Break Cell Found
[11:32:11] reader: end of chapter 8 (media 8) reached at media chapter 9
[11:32:11] reader: done
[11:32:11] thread f0185000 exited ("reader")
Encoding: task 1 of 1, 98.56 % (75.30 fps, avg 75.05 fps, ETA 00h00m01s)[11:32:13] sync: got 1778 frames, 1804 expected
Encoding: task 1 of 1, 98.56 % (75.30 fps, avg 75.05 fps, ETA 00h00m01s)[11:32:14] thread f0491000 exited ("AAC encoder (libfaac)")
[11:32:14] thread f038d000 exited ("H.264/AVC encoder (libx264)")
[11:32:14] thread f040f000 exited ("AC3 decoder")
[11:32:14] thread f030b000 exited ("Renderer")
[11:32:14] thread f0289000 exited ("MPEG-2 decoder (libmpeg2)")
[11:32:14] thread f0289000 joined ("MPEG-2 decoder (libmpeg2)")
[11:32:14] thread f030b000 joined ("Renderer")
[11:32:14] render: dropped frames: 0 (0 ticks)
[11:32:14] render: extended frames: 0 (0 ticks)
[11:32:14] render: Lost time: 0 frames (0 ticks)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 2 buffer(s)
[11:32:14] thread f038d000 joined ("H.264/AVC encoder (libx264)")
x264 [info]: slice I:10    Avg QP:11.30  size: 16151  PSNR Mean Y:50.67 U:51.38 V:51.01 Avg:50.83 Global:50.50
x264 [info]: slice P:1766  Avg QP:14.14  size:  5352  PSNR Mean Y:47.39 U:47.98 V:47.39 Avg:47.48 Global:47.06
x264 [info]: mb I  I16..4: 12.5%  0.0% 87.5%
x264 [info]: mb P  I16..4:  3.7%  0.0%  3.8%  P16..4: 33.0% 27.6% 26.6%  0.0%  0.0%    skip: 5.4%
x264 [info]: final ratefactor: 12.23
x264 [info]: SSIM Mean Y:0.9921712
x264 [info]: PSNR Mean Y:47.408 U:48.002 V:47.406 Avg:47.499 Global:47.076 kb/s:1038.16
[11:32:14] thread f040f000 joined ("AC3 decoder")
[11:32:14] thread f0491000 joined ("AAC encoder (libfaac)")
[11:32:14] thread f0185000 joined ("reader")
[11:32:14] mux: file size, 10829996 bytes
[11:32:14] mux: track 0, 9613102 bytes, 1038.22 kbps
[11:32:14] mux: video bitrate error, +353852 bytes
[11:32:14] mux: track 1, 1184724 bytes, 127.95 kbps
[11:32:14] mux: overhead, 6.48 bytes per frame
[11:32:14] thread f0207000 exited ("muxer")
[11:32:14] thread f0207000 joined ("muxer")
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 0 buffer(s)
[11:32:14] fifo_close: trashing 6 buffer(s)
[11:32:14] Freed 3 buffers of size 512
[11:32:14] Freed 3 buffers of size 1024
[11:32:14] Freed 2048 buffers of size 2048
[11:32:14] Freed 0 buffers of size 4096
[11:32:14] Freed 0 buffers of size 8192
[11:32:14] Freed 35 buffers of size 16384
[11:32:14] Freed 0 buffers of size 32768
[11:32:14] Freed 68 buffers of size 518400
[11:32:14] Allocated 40023552 bytes of buffers on this pass and Freed 40023552 bytes, 0 bytes leaked
[11:32:14] thread f0103000 exited ("work")
[11:32:14] thread f0103000 joined ("work")
[11:32:14] libhb: work result = 0

Rip done!
[11:32:14] thread f0081000 exited ("libhb")
[11:32:14] thread f0081000 joined ("libhb")
HandBrake has exited.
[11:32:14] hb_init: checking cpu count
[11:32:14] hb_init: starting libhb thread
[11:32:14] thread f0081000 started ("libhb")
HandBrake 0.9.1 (2007100800) - http://handbrake.m0k.org/
2 CPUs detected
Opening /Users/jonr/Movies/DVD_VIDEO...
[11:32:14] hb_scan: path=/Users/jonr/Movies/DVD_VIDEO, title_index=1
[11:32:14] thread f0103000 started ("scan")
[11:32:14] scan: trying to open with libdvdread
[11:32:14] scan: DVD has 5 title(s)
[11:32:14] scan: scanning title 1
[11:32:14] scan: opening IFO for VTS 2
[11:32:14] pgc_id: 1, pgn: 1: pgc: 0x7018d0
[11:32:14] scan: vts=2, ttn=1, cells=0->24, blocks=0->3318433, 3318434 blocks
[11:32:14] scan: duration is 01:58:25 (7105000 ms)
[11:32:14] scan: checking audio 1
[11:32:14] scan: id=80bd, lang=English (AC3), 3cc=eng
[11:32:14] scan: checking audio 2
[11:32:14] scan: id=81bd, lang=English (AC3), 3cc=eng
[11:32:14] scan: checking audio 3
[11:32:14] scan: id=82bd, lang=English (AC3), 3cc=eng
[11:32:14] scan: checking audio 4
[11:32:14] scan: id=83bd, lang=English (AC3), 3cc=eng
[11:32:14] scan: checking audio 5
[11:32:14] scan: id=84bd, lang=English (AC3), 3cc=eng
[11:32:14] scan: checking audio 6
[11:32:14] scan: id=8dbd, lang=English (DTS), 3cc=eng
[11:32:14] scan: checking subtitle 1
[11:32:14] scan: id=21bd, lang=English, 3cc=eng
[11:32:14] scan: title 1 has 23 chapters
[11:32:14] scan: chap 1 c=0->1, b=0->166678 (166679), 362603 ms
[11:32:14] scan: chap 2 c=2->2, b=166679->413695 (247017), 507416 ms
[11:32:14] scan: chap 3 c=3->3, b=413696->640900 (227205), 497450 ms
[11:32:14] scan: chap 4 c=4->4, b=640901->770821 (129921), 283532 ms
[11:32:14] scan: chap 5 c=5->5, b=770822->883743 (112922), 238361 ms
[11:32:14] scan: chap 6 c=6->6, b=883744->1119528 (235785), 453404 ms
[11:32:14] scan: chap 7 c=7->7, b=1119529->1274496 (154968), 343424 ms
[11:32:14] scan: chap 8 c=8->8, b=1274497->1309749 (35253), 74260 ms
[11:32:14] scan: chap 9 c=9->9, b=1309750->1476110 (166361), 390453 ms
[11:32:14] scan: chap 10 c=10->10, b=1476111->1607446 (131336), 278404 ms
[11:32:14] scan: chap 11 c=11->11, b=1607447->1723796 (116350), 260323 ms
[11:32:14] scan: chap 12 c=12->13, b=1723797->1913499 (189703), 406573 ms
[11:32:14] scan: chap 13 c=14->14, b=1913500->2041986 (128487), 259278 ms
[11:32:14] scan: chap 14 c=15->15, b=2041987->2245830 (203844), 427450 ms
[11:32:14] scan: chap 15 c=16->16, b=2245831->2359338 (113508), 247468 ms
[11:32:14] scan: chap 16 c=17->17, b=2359339->2499502 (140164), 302414 ms
[11:32:14] scan: chap 17 c=18->18, b=2499503->2611539 (112037), 256230 ms
[11:32:14] scan: chap 18 c=19->19, b=2611540->2749521 (137982), 297476 ms
[11:32:14] scan: chap 19 c=20->20, b=2749522->2847022 (97501), 189421 ms
[11:32:14] scan: chap 20 c=21->21, b=2847023->3002376 (155354), 351454 ms
[11:32:14] scan: chap 21 c=22->22, b=3002377->3097643 (95267), 194169 ms
[11:32:14] scan: chap 22 c=23->23, b=3097644->3318246 (220603), 482415 ms
[11:32:14] scan: chap 23 c=24->24, b=3318247->3318433 (187), 1010 ms
[11:32:14] scan: aspect = 16
[11:32:14] scan: decoding previews for title 1
[11:32:14] scan: preview 1
[11:32:14] scan: AC3, rate=48000Hz, bitrate=192000
[11:32:14] scan: AC3, rate=48000Hz, bitrate=192000
[11:32:14] scan: AC3, rate=48000Hz, bitrate=192000
[11:32:14] scan: AC3, rate=48000Hz, bitrate=192000
[11:32:14] scan: checking for DCA syncinfo
[11:32:14] scan: DCA, rate=48000Hz, bitrate=768000
[11:32:14] scan: AC3, rate=48000Hz, bitrate=448000
[11:32:14] scan: preview 2
[11:32:14] scan: preview 3
[11:32:14] scan: preview 4
[11:32:14] scan: preview 5
Scanning title 1...
[11:32:14] scan: preview 6
[11:32:14] Title's mostly progressive NTSC, setting fps to 23.976
[11:32:14] scan: preview 7
[11:32:15] scan: preview 8
[11:32:15] scan: preview 9
[11:32:15] scan: preview 10
Scanning title 1...
[11:32:15] scan: 720x480, 23.976 fps, autocrop = 54/60/6/4
[11:32:15] scan: title (0) job->width:704, job->height:304
[11:32:15] thread f0103000 exited ("scan")
[11:32:15] thread f0103000 joined ("scan")
[11:32:15] libhb: scan thread found 1 valid title(s)
+ title 1:
  + vts 2, ttn 1, cells 0->24 (3318434 blocks)
  + duration: 01:58:25
  + size: 720x480, aspect: 1.78, 23.976 fps
  + autocrop: 54/60/6/4
  + chapters:
    + 1: cells 0->1, 166679 blocks, duration 00:06:03
    + 2: cells 2->2, 247017 blocks, duration 00:08:27
    + 3: cells 3->3, 227205 blocks, duration 00:08:17
    + 4: cells 4->4, 129921 blocks, duration 00:04:44
    + 5: cells 5->5, 112922 blocks, duration 00:03:58
    + 6: cells 6->6, 235785 blocks, duration 00:07:33
    + 7: cells 7->7, 154968 blocks, duration 00:05:43
    + 8: cells 8->8, 35253 blocks, duration 00:01:14
    + 9: cells 9->9, 166361 blocks, duration 00:06:30
    + 10: cells 10->10, 131336 blocks, duration 00:04:38
    + 11: cells 11->11, 116350 blocks, duration 00:04:20
    + 12: cells 12->13, 189703 blocks, duration 00:06:47
    + 13: cells 14->14, 128487 blocks, duration 00:04:19
    + 14: cells 15->15, 203844 blocks, duration 00:07:07
    + 15: cells 16->16, 113508 blocks, duration 00:04:07
    + 16: cells 17->17, 140164 blocks, duration 00:05:02
    + 17: cells 18->18, 112037 blocks, duration 00:04:16
    + 18: cells 19->19, 137982 blocks, duration 00:04:57
    + 19: cells 20->20, 97501 blocks, duration 00:03:09
    + 20: cells 21->21, 155354 blocks, duration 00:05:51
    + 21: cells 22->22, 95267 blocks, duration 00:03:14
    + 22: cells 23->23, 220603 blocks, duration 00:08:02
    + 23: cells 24->24, 187 blocks, duration 00:00:01
  + audio tracks:
    + 1, English (AC3) (Dolby Surround), 48000Hz, 192000bps
    + 2, English (AC3) (5.1 ch), 48000Hz, 448000bps
    + 3, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 4, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 5, English (AC3) (2.0 ch), 48000Hz, 192000bps
    + 6, English (DTS) (5.1 ch), 48000Hz, 768000bps
  + subtitle tracks:
    + 1, English (iso639-2: eng)
[11:32:15] thread f0103000 started ("work")
[11:32:15] 1 job(s) to process
[11:32:15] starting job
[11:32:15]  + device /Users/jonr/Movies/DVD_VIDEO
[11:32:15]  + title 1, chapter(s) 8 to 8
[11:32:15]  + 720x480 -> 710x366, crop 54/60/6/4
[11:32:15]  + filters
[11:32:15]  + 23.976 fps, video bitrate 1000 kbps, pass 0
[11:32:15]  + PixelRatio: 1, width:710, height: 366
[11:32:15]  + encoder x264
[11:32:15]  + audio 128 kbps, 44100 Hz
[11:32:15]  + encoder faac
[11:32:15]    + 80bd, English (AC3) (Dolby Surround)
[11:32:15]      + Requested mixdown: Dolby Pro Logic II (HB_AMIXDOWN_DOLBYPLII)
[11:32:15]      + Actual mixdown: Dolby Surround (HB_AMIXDOWN_DOLBY)
[11:32:15] thread f0185000 started ("reader")
[11:32:15]  + output: /Volumes/MyBook/big.mp4
[11:32:15] thread f0207000 started ("muxer")
[11:32:15] thread f0289000 started ("MPEG-2 decoder (libmpeg2)")
[11:32:15] thread f030b000 started ("Renderer")
[11:32:15] encx264: keyint-min: 24, keyint-max: 240
[11:32:15] encx264: encoding with stored aspect 32/27
[11:32:15] encx264: opening libx264 (pass 0)
x264 [warning]: width or height not divisible by 16 (710x366), compression will suffer.
x264 [info]: using SAR=32/27
x264 [info]: using cpu capabilities: Altivec 
[11:32:15] thread f038d000 started ("H.264/AVC encoder (libx264)")
No accelerated IMDCT transform found
[11:32:15] thread f040f000 started ("AC3 decoder")
[11:32:15] dvd: Beginning of Cell (8) at block 1274497
[11:32:15] a52_syncinfo failed
[11:32:15] a52_syncinfo ok
[11:32:15] thread f0491000 started ("AAC encoder (libfaac)")
[11:32:15] sync: expecting 1804 video frames
[11:32:15] sync: first pts is 241979469
Encoding: task 1 of 1, 88.30 % (29.79 fps, avg 30.28 fps, ETA 00h00m07s)[11:33:08] dvd: End of Cell (8) at block 1309344
Encoding: task 1 of 1, 88.91 % (29.79 fps, avg 30.28 fps, ETA 00h00m07s)[11:33:08] dvd: Beginning of Cell (9) at block 1309750
[11:33:08] dvd: Chapter Break Cell Found
[11:33:08] reader: end of chapter 8 (media 8) reached at media chapter 9
[11:33:08] reader: done
[11:33:08] thread f0185000 exited ("reader")
Encoding: task 1 of 1, 98.34 % (31.64 fps, avg 30.43 fps, ETA 00h00m01s)[11:33:14] sync: got 1778 frames, 1804 expected
Encoding: task 1 of 1, 98.56 % (31.64 fps, avg 30.43 fps, ETA 00h00m01s)[11:33:15] thread f040f000 exited ("AC3 decoder")
[11:33:15] thread f030b000 exited ("Renderer")
[11:33:15] thread f0491000 exited ("AAC encoder (libfaac)")
[11:33:15] thread f0289000 exited ("MPEG-2 decoder (libmpeg2)")
[11:33:15] thread f0289000 joined ("MPEG-2 decoder (libmpeg2)")
[11:33:15] thread f038d000 exited ("H.264/AVC encoder (libx264)")
[11:33:15] thread f030b000 joined ("Renderer")
[11:33:15] render: dropped frames: 0 (0 ticks)
[11:33:15] render: extended frames: 0 (0 ticks)
[11:33:15] render: Lost time: 0 frames (0 ticks)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 2 buffer(s)
[11:33:15] thread f038d000 joined ("H.264/AVC encoder (libx264)")
x264 [info]: slice I:10    Avg QP:19.90  size: 25347  PSNR Mean Y:45.20 U:37.53 V:33.67 Avg:39.10 Global:38.82
x264 [info]: slice P:1766  Avg QP:22.58  size:  5364  PSNR Mean Y:43.06 U:37.56 V:33.59 Avg:38.65 Global:38.38
x264 [info]: mb I  I16..4: 40.2%  0.0% 59.8%
x264 [info]: mb P  I16..4:  5.6%  0.0%  3.1%  P16..4: 32.8% 17.9%  4.8%  0.0%  0.0%    skip:35.9%
x264 [info]: final ratefactor: 20.74
x264 [info]: SSIM Mean Y:0.9761523
x264 [info]: PSNR Mean Y:43.070 U:37.560 V:33.589 Avg:38.652 Global:38.386 kb/s:1050.51
[11:33:15] thread f040f000 joined ("AC3 decoder")
[11:33:15] mux: track 1, 1184724 bytes, 127.95 kbps
[11:33:15] mux: overhead, 6.48 bytes per frame
[11:33:15] thread f0207000 exited ("muxer")
[11:33:15] thread f0207000 joined ("muxer")
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 0 buffer(s)
[11:33:15] fifo_close: trashing 6 buffer(s)
[11:33:15] Freed 3 buffers of size 512
[11:33:15] Freed 2 buffers of size 1024
[11:33:15] Freed 2048 buffers of size 2048
[11:33:15] Freed 0 buffers of size 4096
[11:33:15] Freed 0 buffers of size 8192
[11:33:15] Freed 35 buffers of size 16384
[11:33:15] Freed 0 buffers of size 32768
Muxing: 0.00 %[11:33:15] Freed 68 buffers of size 518400
[11:33:15] Allocated 40022528 bytes of buffers on this pass and Freed 40022528 bytes, 0 bytes leaked
[11:33:15] thread f0103000 exited ("work")
[11:33:15] thread f0103000 joined ("work")
[11:33:15] libhb: work result = 0

Rip done!
[11:33:15] thread f0081000 exited ("libhb")
[11:33:15] thread f0081000 joined ("libhb")
HandBrake has exited.
Results in:

Code: Select all

Khaybet:hb-conan jonr$ ls -la /Volumes/MyBook/ | egrep "small.mp4|big.mp4"
-rw-r--r--    1 jonr  staff    10944453 Jan 29 11:33 big.mp4
-rw-r--r--    1 jonr  staff    10829996 Jan 29 11:32 small.mp4
User avatar
BradleyS
Moderator
Posts: 1860
Joined: Thu Aug 09, 2007 12:16 pm

Re: File sizes for "iPod High" preset

Post by BradleyS »

I hate to supplement what the other devs have written, but I think it might be all of this "bit" talk that's confusing people. If you have no idea what a bit is, this is for you.

There are 8 bits in a byte.
There are 1024 bytes in a kilobyte (kibibyte, proper).
There are 1024 kilobytes in a megabyte (mebibyte).
There are 1024 megabytes in a gigabyte (gibibyte).
There are 1024 gigabytes in a terabyte (tibibyte).

If your video bitrate is 1500 kilobits per second, and your audio is 128, that's 1628 kiloBITS per second. You can divide by 8 to get kiloBYTES per second, since there are 8 bits in a byte. That's 203.5 kilobytes per second.

Using this advanced wizardry, it is easy to figure out the approximate size of a video once you know its length (bitrate * length, as stated before). If your video was one hour, the duration in seconds is 3600 (that's 60 seconds * 60 minutes). 203.5 * 3600 = 732,600 kilobytes.

Lastly, you might do one last conversion (getting this?). Divide by 1024 to get 715.42 megabytes.

The reason you might end up with a 710MB encode or a 705MB encode, etc., is that the encoder might not actually be able to put exactly 203.5 kilobytes of data in the stream every second. It could be slightly more or slightly less, which makes the resultant file slightly larger or smaller in size. Regardless, the math here is an exact science.

It does not matter whether you are encoding H.264, DivX, Xvid, Theora, Motion JPEG, or whatever. Your resolution is irrelevant. If you increase resolution, you need to compensate by increasing BITRATE. Likewise, when you decrease resolution you can lessen your bitrate.

Finally, an easy way to convert approximate bitrates per resolution. Say you have 640x480 video. Multiply that to get the number of pixels, 307,200. Likewise, 320x240 video is 76,800 pixels. From this, we can conclude that there are 4 times fewer pixels in the latter. Thus, as a *general* rule, it would require approximately 4 times less *video* bitrate (not overall bitrate) to achieve the same quality. Your resulting file will be 4 times smaller in size.

Again, while there are various factors in play that can skew your results slightly, the math here is an exact science, and is perfect for approximations.

Edit: Added tibibyte proper. Thanks jbrjake.
nightstrm
Veteran User
Posts: 1887
Joined: Fri Mar 23, 2007 5:43 am

Re: File sizes for "iPod High" preset

Post by nightstrm »

BradleyS wrote:I hate to supplement what the other devs have written, but I think it might be all of this "bit" talk that's confusing people. If you have no idea what a bit is, this is for you.

There are 8 bits in a byte.
There are 1024 bytes in a kilobyte (kibibyte, proper).
There are 1024 kilobytes in a megabyte (mebibyte).
There are 1024 megabytes in a gigabyte (gibibyte).
There are 1024 gigabytes in a terabyte (tibibyte).

If your video bitrate is 1500 kilobits per second, and your audio is 128, that's 1628 kiloBITS per second. You can divide by 8 to get kiloBYTES per second, since there are 8 bits in a byte. That's 203.5 kilobytes per second.

Using this advanced wizardry, it is easy to figure out the approximate size of a video once you know its length (bitrate * length, as stated before). If your video was one hour, the duration in seconds is 3600 (that's 60 seconds * 60 minutes). 203.5 * 3600 = 732,600 kilobytes.

Lastly, you might do one last conversion (getting this?). Divide by 1024 to get 715.42 megabytes.

The reason you might end up with a 710MB encode or a 705MB encode, etc., is that the encoder might not actually be able to put exactly 203.5 kilobytes of data in the stream every second. It could be slightly more or slightly less, which makes the resultant file slightly larger or smaller in size. Regardless, the math here is an exact science.

It does not matter whether you are encoding H.264, DivX, Xvid, Theora, Motion JPEG, or whatever. Your resolution is irrelevant. If you increase resolution, you need to compensate by increasing BITRATE. Likewise, when you decrease resolution you can lessen your bitrate.

Finally, an easy way to convert approximate bitrates per resolution. Say you have 640x480 video. Multiply that to get the number of pixels, 307,200. Likewise, 320x240 video is 76,800 pixels. From this, we can conclude that there are 4 times fewer pixels in the latter. Thus, as a *general* rule, it would require approximately 4 times less *video* bitrate (not overall bitrate) to achieve the same quality. Your resulting file will be 4 times smaller in size.

Again, while there are various factors in play that can skew your results slightly, the math here is an exact science, and is perfect for approximations.

Edit: Added tibibyte proper. Thanks jbrjake.
This post reminds me of the first day of my first class in college... one of those good old intro classes they make you take when you start in a CSE program. Ah... memories. 8)
User avatar
BradleyS
Moderator
Posts: 1860
Joined: Thu Aug 09, 2007 12:16 pm

Re: File sizes for "iPod High" preset

Post by BradleyS »

This post reminds me of the first day of my first class in college... one of those good old intro classes they make you take when you start in a CSE program. Ah... memories. 8)
Heh. For me it was, "how to explain bits to people without being condescending". Sorta ended up like a class, huh. I could have been a jerk about it. :)
Se7enLC
Posts: 9
Joined: Wed Jan 09, 2008 6:41 pm

Re: File sizes for "iPod High" preset

Post by Se7enLC »

jbrjake wrote:You people are insane.

A bit is a bit is a bit is a bit is a bit is a bit is a bit!

You can do an encode at a width of 320 or at a full anamorphic width, but as long as you use the same bitrate they will be pretty much the same size, except for minor fluctuations in container overhead.

Code: Select all

$ ./HandBrakeCLI -i ~/Movies/DVD_VIDEO -c 8 -e x264 -w 320 -b 1000 -v -o /Volumes/MyBook/small.mp4
$./HandBrakeCLI -i ~/Movies/DVD_VIDEO -c 8 -p -b 1000 -v -o /Volumes/MyBook/big.mp4 -e x264

<snip>

Results in:

Code: Select all

Khaybet:hb-conan jonr$ ls -la /Volumes/MyBook/ | egrep "small.mp4|big.mp4"
-rw-r--r--    1 jonr  staff    10944453 Jan 29 11:33 big.mp4
-rw-r--r--    1 jonr  staff    10829996 Jan 29 11:32 small.mp4
Yes, I understand that part. We all understand what a bit is. When you specify a bitrate, it ensures that the resulting filesize will be approx the same as any other video of the same length and bitrate, regardless of resolution. And the example you posted proves that quite nicely. That should clear up the confusion anybody else had before.

My question, however, was about the OTHER example. The one where the bitrate was NOT specified. There are screenshots posted that clearly show a 320x200 video with a larger filesize than a 640x480 video. Yes, we've established that it is bitrate and not resolution that defines the resulting filesize. But my question remains unanswered - why is it that the default bitrate for 320x200 is such that it results in a larger filesize than the 640x480 video? The example clearly shows that the only difference in the commandline was the specification of a resolution.

Logic would dictate that if you don't specify a bitrate manually, it should do one of two things:
1). It should use the same bitrate for everything. If that's the case, both files should be the same size, right?
2). It should intelligently pick a bitrate to provide good quality. If that were the case, the larger resolution should have used a higher bitrate, and thus had a larger filesize.
3). I guess since it didn't do either of those two things, it must have decided for some reason to use a higher bitrate for the lower resolution video. WHY?
jbrjake
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Re: File sizes for "iPod High" preset

Post by jbrjake »

Se7enLC wrote:Yes, I understand that part. We all understand what a bit is.
If we "all" understood then Polygon wouldn't have insisted that "that can't be right" and BradleyS wouldn't have felt compelled to turn the thread into a remedial computer science class.
My question, however, was about the OTHER example. The one where the bitrate was NOT specified.
I've ignored it because I can't reproduce it, indicating to me that this is a PEBKAC issue, like so much else in this thread. I just did two ffmpeg encodes at default bitrate, the 720 width one came out at 1158kb/s, the 320 width one came out at 1050kb/s. That's damned close for one-pass in lavc.
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