Audio/Video out of sync

[CheloXL]

Hi!,
I have two nice streams, one for audio and another for video. The audio stream was converted to AAC using beSweet, and the video was created with vdub/xvid. So far, so good.

Now i want to create an mp4 file with the audio and the video, using mp4box. All work without errors, but the video is out of sync. I of course adjusted the frame rate using the fps command, but it seems that mp4box is not taking that into account. The video seems to play faster.

Playing the file in MPC and taking a look at the statistics window i see that the frame rate is, indeed, 23.9x (should be 23.976). But again, the video seems to play faster than the audio...

Ideas?
Thanks in advance!,

[bond]

-fps is only taken into account when muxing from raw streams...

[DigitalDeviant]

Is the audio evenly out of synch through the whole video? If so you may need to add a negative delay to the audio stream, though I'm not sure how to do that in mp4box.

[CheloXL]

For raw streams i understand: Video demuxed from an AVI container (done with YAMP) and audio in AAC (ISO 13818-7) format (not into an mp4 container). Am i right?

And no, the delay gets worse at the end (that´s why i think is a FPS problem)

[bond]

For raw streams i understand: Video demuxed from an AVI container (done with YAMP)yep
but if the video in avi already has the correct framerate you dont need to demux to raw, but simply remux from avi to mp4 with yamb (only possible if the video is mpeg-4 asp (divx, xvid...)) and the same framerate as in the avi will be used in the mp4 too

and audio in AAC (ISO 13818-7) format (not into an mp4 container). Am i right?no, audio doesnt have a framerate

And no, the delay gets worse at the end (that´s why i think is a FPS problem) thats indeed a fps problem

[CheloXL]

The video was compressed with xvid. I didn´t know that you can mux directly from the avi container. Nice to know!... now the problem is... i deleted the avi files and have only the raw ones! :(

I know that audio doesn´t have framerate, but i did that to make sure that mp4box doesn´t take the framerate from the (audio) mp4 file (i thought that the fps problem could be a bug in mp4box).

This is the command line i´m using:

MP4Box.exe -add "VTS_03_12_video.cmp" -fps 23.976 -add "VTS_03_1 T01 2_0ch 192Kbps DELAY 0ms_track1.aac"

If i try to open the file with osmo, it throws an error (Stream setup failure) and in the object description, the video is correctly identified, but the audio no (Object Descriptor ID 10
- Unknown duration) (in the "general" tab).
On the streams tab, the audio is recognized

(** Stream ID 101 - Clock ID 1 **
Audio Stream - media type: MPEG-4
Buffer Size 935
Average Bitrate 107480 bps
Maximum Bitrate 134600 bps
Stream Clock Resolution 48000
Stream Language: spa)

I already tried all what i could think should change that, without success...

[bond]

how did you extract the video stream out of the .avi?
did you use packed bitstream?

[CheloXL]

Using yamb, and yes, i used packed bitstream.

[bond]

Using yamb, and yes, i used packed bitstream.packed bitstream is evil, you still have the dummy n-vops in your stream

try adding -packed to the cmdl in mp4box

[CheloXL]

Same result :(

[bond]

does the file play in other players, like mplayer, videolan or directshow-based solutions (haali, mpc, 3ivx)?

[foxyshadis]

Try using mkvmerge/mmg with --engage native_mpeg4, which will undo any avi hacks, then use yamb to convert it to mp4. Hopefully it'll load the raw stream.

[bond]

Try using mkvmerge/mmg with --engage native_mpeg4, which will undo any avi hackshe doesnt have avi files anymore, only raw streams

then use yamb to convert it to mp4yamb doesnt support mkv input

[CheloXL]

The file plays in MPC (audio/video sync problem) and in Osmo (without audio as noted above).
If anyone want, i can put the files on an FTP (25mb video, 2mb audio)....

[bond]

The file plays in MPC (audio/video sync problem) and in Osmo (without audio as noted above).
If anyone want, i can put the files on an FTP (25mb video, 2mb audio)....upload the raw streams plz

[CheloXL]

Here you have:

http://www.extremefx.com.ar/doom9/video.cmp
http://www.extremefx.com.ar/doom9/audio.aac

Hope you can find the problem!

[bond]

after playing around a little bit it seems the video needs a framerate around 19.2 or so
as i assume the original source didnt have this framerate i assume you did something strange when encoding the video (dropping frames), so how exactly did you encode the video? what was your .avs script? what were all your xvid settings?

[CheloXL]

The video was originally in 29.97 fps. I then created a d2v file (DGIndex -> Field operation: forced film)(edit: i also added the _A string to the d2v file to get the output in YUY2), created an avi with VFAPI and compressed in vdub with xvid, 2 pass (Motion search 6, VHQ 1, VHQ on bframes, Chroma motion, trellis, target br 1200)... nothing strange (the same settings i always use for avi files).

What is strange is that from that DVD i have the main movie and another short one. The movie has the same problem as the file i uploaded, but the short one works perfect, and i used the same settings for all the movies. That´s why i don´t understand what´s wrong.

[bond]

are you sure this vfapi avi has 29.97fps? why dont you use .avs?

[CheloXL]

The vfapi avi was 23.976 (the original file was 29.97, but when i created the d2v file with DGIndex, it was converted to 23.976... i always do that).

I don´t use .avs because.. well.. i never used it :) Maybe it´s time to start using avisynt... (i have it installed, but never got the time to investigate it)...