What's a good setting for reducing file size?

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Ctrl+Z
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What's a good setting for reducing file size?

Post by Ctrl+Z » Fri May 28, 2010 7:51 am

I am trying to put some movies on my ipod touch, but most of the space has gone to music and I prefer to carry more movies of a lower quality so I have options. Has anyone got any settings they use for optimizing the file size?

I have tried all of the presets and I would really prefer to go smaller if I can. I don't mind losing a reasonable amount of quality. I have looked all over this site and the internet as a whole and everyone seems to be optimizing quality. How small can the file size potentially go at 480 width?

TedJ
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Re: What's a good setting for reducing file size?

Post by TedJ » Fri May 28, 2010 9:26 am

Try using the standard iPhone preset, but increase RF to 23... quality loss should be imperceptible on the Touch's screen and it will reduce filesize considerably.

Ctrl+Z
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Re: What's a good setting for reducing file size?

Post by Ctrl+Z » Fri May 28, 2010 10:43 am

Wow yeah. That's a great result for the amount of effort put in.

Any other tips for getting it down even further? I really don't mind if it takes a long time to process. What are some areas I might be able to experiment with that typically lead to smaller files with a modest trade-off in quality?

Thanks

creamyhorror
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Re: What's a good setting for reducing file size?

Post by creamyhorror » Fri May 28, 2010 2:06 pm

To reduce bitrate (file size) along with quality, increase the RF.

Ctrl+Z
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Re: What's a good setting for reducing file size?

Post by Ctrl+Z » Fri May 28, 2010 2:19 pm

Thanks. Yeah, I had figured that much out already - I read all the documentation and all, and also many posts. I was just hoping someone might be able to give me some tips on using the more advanced features. Here's a couple of ideas I imagined might be possible:

1. I have heard many people speak of the trade off between quality, size, and production speed. In my case I really, really, really don't care about the speed - are there any features that allow me to reduce size by trading for speed rather than on quality.

2. Or maybe as you said, I could increase the RF. Are there any filters or advanced features that will help disguise the reduced quality?

mduell
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Re: What's a good setting for reducing file size?

Post by mduell » Fri May 28, 2010 4:23 pm

Keep raising the rate factor until you can't watch it any more. If you're OK at RF 30, start dropping the resolution.

yejun
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Re: What's a good setting for reducing file size?

Post by yejun » Thu Jun 03, 2010 4:34 pm

Increase subpixel motion estimation to 8 or 9. Turn on denoise and deblock. Use 2 pass encoding.

dynaflash
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Re: What's a good setting for reducing file size?

Post by dynaflash » Thu Jun 03, 2010 5:12 pm

yejun wrote:Increase subpixel motion estimation to 8 or 9. Turn on denoise and deblock. Use 2 pass encoding.
hmm, be careful though with denoise and deblock, watch for "smearing" or in other words a very soft looking picture with little detail. They work, but imo need to really be checked for crappy images when used on a source that doesn't need it.

creamyhorror
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Re: What's a good setting for reducing file size?

Post by creamyhorror » Thu Jun 03, 2010 6:06 pm

Ctrl+Z wrote:1. I have heard many people speak of the trade off between quality, size, and production speed. In my case I really, really, really don't care about the speed - are there any features that allow me to reduce size by trading for speed rather than on quality.
You previously asked how to reduce bitrate with a modest trade-off on quality. RF is the right tool for that purpose; that's why I mentioned it alone.

Using higher settings generally improves your compression efficiency, i.e. the quality per bit (in crude terms). But you don't have a guarantee that the bitrate will change as you wish - it often goes up or stays constant. That's why you ultimately have to change the RF value along with any other options you increase.
2. Or maybe as you said, I could increase the RF. Are there any filters or advanced features that will help disguise the reduced quality?
All sorts of features will improve compression efficiency. You can refer to the x264 presets system to get ideas on what settings to tweak.

Filtering is risky, as dynaflash says. It's easy to do on Windows if you're working with Avisynth's filters and have instant feedback via AvsP on the results of the filters, but Handbrake doesn't natively support input from Avisynth AFAIK (someone correct me if I'm wrong). I'm not sure about the strength or effectiveness of the denoise/deblock filters in HB.

dynaflash
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Re: What's a good setting for reducing file size?

Post by dynaflash » Thu Jun 03, 2010 6:18 pm

creamyhorror wrote: Filtering is risky, as dynaflash says. It's easy to do on Windows if you're working with Avisynth's filters and have instant feedback via AvsP on the results of the filters, but Handbrake doesn't natively support input from Avisynth AFAIK (someone correct me if I'm wrong). I'm not sure about the strength or effectiveness of the denoise/deblock filters in HB.
Correct, HB's denoise and deblock filters work great depending on the source and what you want. Deblock imho can be a bit heavy handed as well as denoise. Of course depending on your source and what you wish to obtain they may be right for the job. Use the weakest settings on each and see if you like it on a once chapter test. Or better yet use the live preview feature in all three guis to do a quick test. HB's filters are used on live previews. A good way to grab a 60 second sample and see if you like the results before doing a much longer encode.

Oh and correct HandBrake does not natively support input from Avisynth.

simonx314
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Re: What's a good setting for reducing file size?

Post by simonx314 » Fri Jun 25, 2010 8:47 am

I get full length movies down to less than 150mb. Use these advanced settings. Reference frames 5, mixed references, b-frames 5, adaptive b frames optimal, direct prediction temporal, weighted b frames, pyramidal b-frames, motion estimation uneven multihexagon, subpixel me 9, motion estimation 32 (or more if you have spare hours), 8x8 DCT, CABAC, Trellis 1, psy-rd=1.0,0.2.

These settings will work on a 3GS, lower b-frames to 3 and reference frames to 4 on older hardware if you encounter playback issues such as stuttering, green blocky artifacts, or iTunes refuses to sync. If you have to disable pyramidal, weighted b-frames, mixed references, as these settings save space by requiring the CPU to work harder to reassemble the picture.

Don't forget to crop off unwanted/black borders and deinterlace if necessary. Encoders use 16x16 pixel blocks so it is best if your dimensions are divisible by 16. Check imdb.com for the content's aspect and use these settings.

1.33 SD TV 432x320
1.66 Euro Film 480x288
16:9 HD TV 480x272
1.85 Film 480x256
2.39 Wide film 480x208

Now set handbrake to only encode one chapter, preferably one that's only 1 or 2 minutes and has a mix of high and low motion scenes. Start at 200kbps and keep lowering until you see artifacts, some movies I have gotten down to 100kbps and they still look fine. For audio I use 96kbps mono. You gotta sacrifice a little if you want to carry around 50 of your favorite movies. Use the lowest bitrate you can tolerate then do a two pass avg. bitrate encode on the whole movie.

Good compressionists will do many tests with short clips until they find just the right settings, with practice you can guess and get good results on your first or second test. Don't encode a whole movie for hours and have to redo it all because of one small mistake.

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Rodeo
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Re: What's a good setting for reducing file size?

Post by Rodeo » Fri Jun 25, 2010 2:18 pm

simonx314 wrote:I get full length movies down to less than 150mb. Use these advanced settings. Reference frames 5, mixed references, b-frames 5, adaptive b frames optimal, direct prediction temporal, weighted b frames, pyramidal b-frames, motion estimation uneven multihexagon, subpixel me 9, motion estimation 32 (or more if you have spare hours), 8x8 DCT, CABAC, Trellis 1, psy-rd=1.0,0.2.
There's no reason to go above 24 for merange, especially considering that other settings aren't maxed out (e.g. trellis 1 -> 2 will increase compression efficiency more than increasing merange from 16 to 24 or beyond).

Also, direct should be set to either spatial (the default) or auto. Always temporal is worse that always spatial for many clips, and for clips that actually benefit from it (i.e. that "love temporal"), auto will give equally good results.

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