AVIDEMUX syncing problems

[dan_man555]

I am trying to convert my MKV video into a zune compatible video, with hardcoded subtitles.

It works fine, except the video doesn't sync with the audio.

The only settings i change is the auto zune script, and add the subtitles filter, and i double check that the frame rate is set to 23.976 fps. I've also tried it with avs proxy gui with ffvideosource, and dshowsource (which gives me no sound).
Media player classic plays it properly.

Here's the information from the video:

General
Unique ID                        : 227555312679119844949716040911072281253 (0xAB318F1F2A9A193385C3D71CE15042A5)
Complete name                    : C:\MYVIDEO.mkv
Format                           : Matroska
Format version                   : Version 1
File size                        : 232 MiB
Duration                         : 23mn 44s
Overall bit rate                 : 1 366 Kbps
Encoded date                     : UTC 2008-08-28 01:41:13
Writing application              : mkvmerge v2.2.0 ('Turn It On Again') built on Mar  4 2008 12:58:26
Writing library                  : libebml v0.7.7 + libmatroska v0.8.1
Attachment                       : Yes / Yes / Yes

Video
ID                               : 1
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : High@L4.0
Format settings, CABAC           : Yes
Format settings, ReFrames        : 16 frames
Format settings, GOP             : N=1
Codec ID                         : V_MPEG4/ISO/AVC
Duration                         : 23mn 44s
Nominal bit rate                 : 1 170 Kbps
Width                            : 720 pixels
Height                           : 480 pixels
Display aspect ratio             : 16:9
Original display aspect ratio    : 3:2
Frame rate                       : 23.976 fps
Original frame rate              : 22.294 fps
Standard                         : NTSC
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.141
Title                            : MYVIDEO
Writing library                  : x264 core 61 r949M 60c4f7e
Encoding settings                : cabac=1 / ref=16 / deblock=1:1:1 / analyse=0x3:0x113 / me=umh / subme=7 / psy_rd=0.0:0.0 / brdo=1 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / chroma_qp_offset=0 / threads=3 / nr=0 / decimate=1 / mbaff=0 / bframes=16 / b_pyramid=1 / b_adapt=1 / b_bias=0 / direct=3 / wpredb=1 / bime=1 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=2pass / bitrate=1170 / ratetol=1.0 / rceq='blurCplx^(1-qComp)' / qcomp=1.00 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=2:1.10
Language                         : English

Audio
ID                               : 2
Format                           : AAC
Format/Info                      : Advanced Audio Codec
Format profile                   : LC
Codec ID                         : A_AAC
Duration                         : 23mn 44s
Channel(s)                       : 2 channels
Channel positions                : Front: L R
Sampling rate                    : 48.0 KHz
Compression mode                 : Lossy
Title                            : MYVIDEO
Language                         : English

Text
ID                               : 3
Format                           : ASS
Codec ID                         : S_TEXT/ASS
Codec ID/Info                    : Advanced Sub Station Alpha
Compression mode                 : Lossless
Title                            : MYVIDEO
Language                         : English

Any help would be greatly appreciated

[davexnet]

Hard to say, unless it's something to do with this (never seen it before).
Frame rate : 23.976 fps
Original frame rate : 22.294 fps

[dan_man555]

I noticed that too, but I don't know what to do about it.

[davexnet]

How far out is the audio? Is the same amount all the way through?
Or does it get worse as it progresses?

[dan_man555]

worsens as it goes
I'm considering converting it to an mp4 externally, then hardcoding the subtitles after.
I'd rather not have to transcode it twice though
Is there another program that can handle mkv's, hardcode ASS subtitles and has zune format output?

[davexnet]

MakeMKV seems to be popular, but I've never tried it.
https://www.videohelp.com/tools/MakeMKV

[transporterfan]

It may be a bad audio file. It's just a guess.
You could try demuxing the MKV in tsMuxer, remux it to .ts and play to see if it is in sync.
If it doesn't play in sync at least you can get the timing offset for your zune encoder with MPC.
It should only take a few minutes.

Or convert the audio to MP3 then encode to zune profile.
There have been a couple of posts like this in the past where converting corrected the issues for other devices.
The most likely cause is the strange frame rate difference.

[dan_man555]

The remux is also out of sync, and converting audio to mp3 makes no difference.

I don't understand why the original plays properly, but the conversion won't.

[transporterfan]

Did you find the required delay with MPC?
If so, you can enter it in tsMuxer (General track options) if you click on the sound track. Mux it with the delay to a new file.
Hopefully you can use the new file with your sub file and convert to zune.

Edit:

Sorry, missed your question. Scrolled off screen. Lol.

To find the delay open movie in MPC
In Play>Audio>Options
Select tick box 'Audio time shift(ms):'
Play about with positive or negative values (depending on if sound is behind the video or ahead)
Scroll to end of video to make sure it's in sync. When it is, that's your delay figure.
Clear tickbox when your done!

[dan_man555]

How do i get the information i need from MPC?
I never touched the settings in it.
Does it matter that it says 'Playing [DXVA]'?

[transporterfan]

No it doesn't matter.
It can take a lot of time to find the delay. It could be anything from zero to god-knows-what (+ or -).
You get better at guessing with practice.
Don't forget it's in milliseconds so 1 second =1000 milliseconds.

Edit: some files just defy syncing...if all else fails, find a new source.

[dan_man555]

I might just try and find a new source like you said
Thanks anyway

[davexnet]

Is this a source you can share with the board? Perhaps make it available, and somebody will check it out.

[mbluett]

I have been experiencing this as well with AVIDemux v2.6.0 but only on some videos. All my videos are recorded using a Hauppauge Colossus. The ones that seem to cause the problem are 1920x1080. These videos play perfectly in VLC and in NextPVR using the ffdshow decoder.

AVIDEmux 2.6 appears to use the "lavcodec" (libvpx) for decoding. This may be the same codec that is available for use in NextPVR. The reason I mention this is because the LAV codec causes sync problems when used with NextPVR as well.

I found this info on the VPX library website. It mentions the stuttering problem and how to resolve it. The problem is that AVIDemux does not provide a way to disable this feature.

unsigned int vpx_codec_enc_cfg::rc_dropframe_thresh
Temporal resampling configuration, if supported by the codec.

Temporal resampling allows the codec to "drop" frames as a strategy to meet its target data rate. This can cause temporal discontinuities in the encoded video, which may appear as stuttering during playback. This trade-off is often acceptable, but for many applications is not. It can be disabled in these cases.

Note that not all codecs support this feature. All vpx VPx codecs do. For other codecs, consult the documentation for that algorithm.

This threshold is described as a percentage of the target data buffer. When the data buffer falls below this percentage of fullness, a dropped frame is indicated. Set the threshold to zero (0) to disable this feature.

I have been testing VideoReDo v4 (with H.264) and it works great (so far). It uses the Mainconcept decoder. I have found that this decoder works very well with NextPVR as well. I may just end up spending the money and using VideoReDo. The most important thing for me is getting the job done in an efficient and timely manner and not having to fight with software.

Maybe the developer of AVIDemux should consider using a different decoder codec or provide us with a way to disable the feature I mentioned above (assuming that fixes the stuttering and sync issues I have experienced). The Mainconcept codec has licensing fees associated with it, but the ffdshow codec does not. Since the ffdshow codec works very well with NextPVR it is likely to work just as well with AVIDemux.

Comments?

[poisondeathray]

libvpx has nothing to do with h.264 . Libvpx is the open source implementation of VP8 (or webm)

you can make a feature request in the avidemux forum, and/or submit a bug report . They will probably ask you to submit a sample stream that illustrates the issue

http://avidemux.org/smuf/index.php

[mbluett]

libvpx has nothing to do with h.264 . Libvpx is the open source implementation of VP8 (or webm)

Yes, sorry. I did get that wrong. I looked in the Video Decoder plugins directory and assumed that was the one. In actuality it is provided in the ffmpeg library and is in "libADM_coreVideoCodec6.dll" (in my case).

What surprises me is that, according to Wikipedia, VLC and AVIDemux use the same ffmpeg library. So why it should work properly in VLC and not in AVIDemux is a somewhat a mystery. I suppose it is possible they are using different versions of the ffmpeg library. Both my VLC and AVIDemux are the latest available.