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Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

General discussion of HandBrake, Video and/or audio transcoding, trends etc.
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Aeropars
Posts: 5
Joined: Wed Sep 06, 2017 7:24 am

Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by Aeropars » Wed Sep 06, 2017 9:40 am

Hi guys,

I've used handbrake for a few years for DVD ripping etc but I've recently started editing video and have come across an issue which seems to be prevalent in a number of editing suites such as Cyberlink Power Director and more professional suites like Adobe Premiere Pro. The specific issue you would see is the audio becoming out of sync with the video.

The issue stems from devices like iPhones shooting video in variable frame rate. Its seems a common agreement that for the most stable editing experience you should use constant frame rate. Where your device doesn't allow you to capture in CFR its been advised to use Handbrake to transcode the files into CFR.

SO I've tried this on an iPhone app called ProMovie and i shot at 1080p, 30fps and 100bps quality. Thats higher than the stock iOS video app.

I export this from my phone and play it using VLC and it plays perfectly fine. When in Premiere Pro, PowerDirector or even the Native Windows 10 video application the audio is out of sync. If I run this through Handbrake converting to CFR at 30 FPS and then try to play the file as before I get the exact same issues as I did with the original file. I've checked the file using MediaInfo and i can see the file has transcoded to a CBR and the bitrate has reduced which seems to suggest that handbrake has done the job.

So whats going on here? Why would both the original file and the transcoded file show the same issues?

Thanks in advance.

rollin_eng
Veteran User
Posts: 2737
Joined: Wed May 04, 2011 11:06 pm

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by rollin_eng » Wed Sep 06, 2017 2:10 pm

Could you please post your logs, instructions can be found here:

https://handbrake.fr/docs/en/latest/hel ... y-log.html

mduell
Veteran User
Posts: 5953
Joined: Sat Apr 21, 2007 8:54 pm

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by mduell » Wed Sep 06, 2017 2:42 pm

Activity Log is required for support requests. See Must Read: How To Get Questions Answered on These Forums for details

Aeropars
Posts: 5
Joined: Wed Sep 06, 2017 7:24 am

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by Aeropars » Fri Sep 08, 2017 11:04 am

Apologies.

Log can be seen here: https://pastebin.com/rCqHswfu

Aeropars
Posts: 5
Joined: Wed Sep 06, 2017 7:24 am

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by Aeropars » Tue Sep 12, 2017 4:40 pm

This is really buggin me. I've tried everything I can think of. Updated graphics drivers, different encode settings and even a different computer but the problem persists.

If it helps I have the details from Media info shown below:

Original:

Code: Select all

General
Complete name                            : C:\Users\Lee\Desktop\Alex\2017-09-03 12-23-12 M0QW 1920x1080 30fps.mov
Format                                   : MPEG-4
Format profile                           : QuickTime
Codec ID                                 : qt   0000.00 (qt  )
File size                                : 641 MiB
Duration                                 : 1 min 46 s
Overall bit rate                         : 50.3 Mb/s
Encoded date                             : UTC 2017-09-03 11:23:12
Tagged date                              : UTC 2017-09-03 11:24:59
Writing library                          : Apple QuickTime

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L5
Format settings, CABAC                   : Yes
Format settings, RefFrames               : 1 frame
Format settings, GOP                     : M=1, N=15
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 1 min 46 s
Bit rate                                 : 50.3 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Variable
Frame rate                               : 30.000 FPS
Minimum frame rate                       : 29.963 FPS
Maximum frame rate                       : 30.038 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.808
Stream size                              : 638 MiB (99%)
Title                                    : Core Media Video
Encoded date                             : UTC 2017-09-03 11:23:12
Tagged date                              : UTC 2017-09-03 11:24:59
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 1 min 46 s
Source duration                          : 1 min 46 s
Bit rate mode                            : Constant
Nominal bit rate                         : 256 kb/s
Channel(s)                               : 1 channel
Channel positions                        : Front: C
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Transcoded:

Code: Select all

Format profile                           : Base Media / Version 2
Codec ID                                 : mp42 (isom/iso2/avc1/mp41)
File size                                : 257 MiB
Duration                                 : 1 min 46 s
Overall bit rate mode                    : Variable
Overall bit rate                         : 20.2 Mb/s
Encoded date                             : UTC 2017-09-12 16:26:08
Tagged date                              : UTC 2017-09-12 16:26:08
Writing application                      : HandBrake 1.0.7 2017040900

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : Main@L4
Format settings, CABAC                   : Yes
Format settings, RefFrames               : 4 frames
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 1 min 46 s
Bit rate                                 : 20.1 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 30.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.323
Stream size                              : 255 MiB (99%)
Writing library                          : x264 core 148 r2708 86b7198
Encoding settings                        : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=30 / rc=crf / mbtree=1 / crf=15.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=20000 / vbv_bufsize=25000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Encoded date                             : UTC 2017-09-12 16:26:08
Tagged date                              : UTC 2017-09-12 16:26:08
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 1 min 46 s
Bit rate mode                            : Variable
Bit rate                                 : 163 kb/s
Channel(s)                               : 2 channels
Channel(s)_Original                      : 1 channel
Channel positions                        : Front: C
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 2.06 MiB (1%)
Title                                    : Mono / Mono
Default                                  : Yes
Alternate group                          : 1
Encoded date                             : UTC 2017-09-12 16:26:08
Tagged date                              : UTC 2017-09-12 16:26:08
Does anyone have any ideas whats going on here?

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BradleyS
Moderator
Posts: 1279
Joined: Thu Aug 09, 2007 12:16 pm

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by BradleyS » Tue Sep 12, 2017 8:45 pm

Try a nightly build and use "align a/v start".

Aeropars
Posts: 5
Joined: Wed Sep 06, 2017 7:24 am

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by Aeropars » Wed Sep 13, 2017 7:25 am

BradleyS wrote:
Tue Sep 12, 2017 8:45 pm
Try a nightly build and use "align a/v start".
Thanks for the reply Bradley. I'm pleased to say that's actually fixed the issue!

Can you give me an understanding why the issue persisted? Just for my sanity more than anything!

User avatar
BradleyS
Moderator
Posts: 1279
Joined: Thu Aug 09, 2007 12:16 pm

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by BradleyS » Wed Sep 13, 2017 8:28 am

Align A/V Start is needed for players that don't understand MP4 Edit Lists. That said, you may want to try the nightly build and disable the feature, just to see if that was the fix or if it was something else in the nightly's improved sync code. We've fixed a variety of issues there.

Aeropars
Posts: 5
Joined: Wed Sep 06, 2017 7:24 am

Re: Using Handbrake to Fix Variable Frame Rate Audio Sync Issues When Editing

Post by Aeropars » Wed Sep 13, 2017 8:42 am

Thanks very much for the information. I'll give that a go!

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