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[HELP] Audio not-in-sync after processing - Printable Version

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Audio not-in-sync after processing - s_noopy - 05.10.2024

  • What Hybrid version did you use?(Windows/Mac/Linux 32/64bit + versions number)
    Windows, 2024-06-16
  • What did happen? If an error message came up what did it exactly say?
    No error. Audio is no longer in sync with the video after processing
  • What did you do to get to the bug? (best thing is a detailed step-by-step guide so that I can reproduce the problem)
    1. Took a footage from a DV camera to a computer using Firewire interface
    2. Merged files using Lossless Cut into an .mkv
    3. Processed the merged files using Hybrid with  a. deinterlacing QTGMC  b. recoding audio to AAC (tried all different codecs, keeping the input sample rate, even tried no recoding but a passthrough to .mkv container in PCM)4. Observed output to be progressively out-of-sync
  • Debug output would be helpful:
    Attached
  • a small sample, which allows the reproduction of the problem would be nice
    Attached a single scene from the original files
    I may not have checked some checkbox to get the properly synced output but it is the first case I found. Footage I have captured from VHS has no sync issues with the same Hybrid processing. It may be a bug though since the input is correctly synced but output not.


RE: Audio not-in-sync after processing - Selur - 05.10.2024

Update to latest version.
Not sure what to do with the sample since:
a. you wrote that you fed Hybrid with an mkv (the attached is a mov)
b. the sample is too short (800ms) to see any sync issues.

Reading that you cut the file before processing it with Hybrid: Does the problem also happen if you process the uncut file with Hybrid?

Looking at the debug output, I noticed, that the MediaInfo output reports:
Delay                                    : 0
Delay                                    : 00:00:00.000
Delay                                    : 00:00:00:00
Delay                                    : 00:00:00.000 (00:00:00:00)
Delay, origin                            : Container
Delay, origin                            : Container
Delay_Original                           : 1520
Delay_Original                           : 1 s 520 ms
Delay_Original                           : 1 s 520 ms
Delay_Original                           : 1 s 520 ms
Delay_Original                           : 00:00:01.520
Delay_Original                           : 00:00:01:13
Delay_Original                           : 00:00:01.520 (00:00:01:13)
Delay_Original_DropFrame                 : No
Delay_Original_Source                    : Stream
Time code of first frame                 : 00:00:01:13
So container reports a delay of 0ms while the video stream itself report 1520ms, which seems strange.
The Audio stream reports a delay of 40ms to the video and will turn into -3ms delay due to the aac encoder delay.
This is the only delay Hybrid cares about and later uses:
mkvmerge --ui-language en -o "C:\Users\Darek\Documents\2024-10-01@23_48_30_7510__07.mkv" --global-tags "C:\Users\Darek\AppData\Local\Temp\mkvtags_2024-10-01@23_48_30_7510__07.xml" -d 0 --default-track 0:yes --color-matrix-coefficients 0:5 --color-range 0:1 --color-transfer-characteristics 0:1 --color-primaries 0:5 --track-name 0:"Core Media Video" --default-duration "0:50/1fps" --aspect-ratio-factor 0:16/15 --fourcc 0:MP4V --no-chapters --compression -1:none --forced-track 0:yes --field-order 0:0 --no-audio --no-subtitles "C:\Users\Darek\AppData\Local\Temp\2024-10-01@23_48_30_7510_05.264" --track-name 0:"Core Media Audio" --default-track 0:yes --sync 0:-3 --forced-track 0:no -a 0 --compression -1:none --no-video --no-subtitles --no-chapters "C:\Users\Darek\AppData\Local\Temp\iId_2_aid_0_DELAY_-3ms_2024-10-01@23_48_30_7510_02.aac" --track-order 0:1,1:2

The used scripts and calls look fine to me, can't see any issues, error messages or warnings.
Only thing that I noticed it that Hybrid assumes the output to have 172612 frames, but x264 reports to have encoded 177516 frames.(which is ~98 seconds), so my suspicion is that there is some problem decoding the source.


A few things come to mind that you can test:
  • if you set Video&Audio processing to passthrough and just remux the file, is it still sync?
  • if the Vapoursynth Preview shows the expected number of frames (I suspect not). Does this change if you use another decoder? (FFMS2 or Bestsource?)
  • if you use your setting and additionally enable "Config->Input->Decoding->CFR output", does that help with the sync issue?
  • if you use some elaborate 'monster' antivirus suite, try whether it helps to disable it.

If that does not help, share a sample of the source that you feed into Hybrid, which allows reproducing the issue. (Test with that sample before sharing it. You can upload the file, for example, to GoogleDrive or similar and share a link here or via pm.)

Cu Selur

RE: Audio not-in-sync after processing - s_noopy - 06.10.2024

Quote:Not sure what to do with the sample since:
a. you wrote that you fed Hybrid with an mkv (the attached is a mov)
b. the sample is too short (800ms) to see any sync issues.
I was hoping that maybe from the source material you would be able to see anything interesting. Mov to mkv conversion was made by the Lossless Cut program which from my knowledge does not re-encode streams but only repackages them. I used Lossless Cut to merge all the individual scenes to a single file to process with a single job. The merged file was in .mkv container which did not exhibit sync problems. Correct me if I am wrong or there is some way to feed 100 mov files into Hybrid so it would output a single file.

Interestingly enough DV codec is not acceptable in .mkv container according to Hybrid but Lossless Cut did it without batting an eye... I could try merging into .mov container

Quote:if you use your setting and additionally enable "Config->Input->Decoding->CFR output", does that help with the sync issue?
Not if I can tell

Quote:if you use some elaborate 'monster' antivirus suite, try whether it helps to disable it.
Windows Defender only

Quote:if you set Video&Audio processing to passthrough and just remux the file, is it still sync?
Nope, it wen't out of sync

Quote:if the Vapoursynth Preview shows the expected number of frames (I suspect not). Does this change if you use another decoder? (FFMS2 or Bestsource?)
Input file frame count: 88758
Vapoursynth Preview frame count: 177516
Output file with audio sync problem frame count: 177335 (roughly 4 seconds missing which is ~out-of-sync value at the end of the video I experience)
Output file with Frame Interpolation for 50 FPS frame count: 172573 frames (I tried that to see if maybe it would help)

I couldn't find the place to change the decoder, could you point me to it?
I'll try to prepare a sample but it may take a while since I have time only at evenings/nights to do stuff on the computer.

Edit: Passthrough, 50 FPS interpolation and checking preview frame count where made on updated Hybrid version (2024-09-29)

RE: Audio not-in-sync after processing - Selur - 06.10.2024

Quote:Mov to mkv conversion was made by the Lossless Cut program which from my knowledge does not re-encode streams but only repackages them.
If you cut on non-key frames reencoding is done, but only for the affected gops.

Quote:I used Lossless Cut to merge all the individual scenes to a single file to process with a single job.
afaik. LosslessCut uses ffmpeg, so the source might be vfr. (MediaInfo only analyses the first xy timecode to decide whether a source is vfr or not, so on merged content you can not reply on it.

Quote:The merged file was in .mkv container which did not exhibit sync problems.
okay.

Quote: Correct me if I am wrong or there is some way to feed 100 mov files into Hybrid so it would output a single file.
No there is not.

Quote:Interestingly enough DV codec is not acceptable in .mkv container according to Hybrid but Lossless Cut did it without batting an eye...
Yes, Hybrid does not support dv in mkv since mkvmerge does not.

Quote: I could try merging into .mov container
That will probably have the same issue, but you can try.

Quote:Nope, it wen't out of sync
Okay, then it's not a general extracting and muxing problem and the source is probably cfr, since Hybrid will ignore time codes if the source isn't detected as vfr or it's told to extract them.

Quote:Input file frame count: 88758
Vapoursynth Preview frame count: 177516
Output file with audio sync problem frame count: 177335 (roughly 4 seconds missing which is ~out-of-sync value at the end of the video I experience)
So, the sync issue is just at the end, starting at a specific point, or do you just notice a sync problem at the end?

Quote: I couldn't find the place to change the decoder, could you point me to it?
The settings under Filtering->Vapoursynth->Misc->Source, determine the source filter.
You can check the Vapoursynth Script View to see which source filter / decoder is used.

Quote: I'll try to prepare a sample but it may take a while since I have time only at evenings/nights to do stuff on the computer.
Ho hurry, from me, but make sure that the sample allows to reproduce the problem.

Cu Selur