A/V Out of Sync: Need help to understand

[MarcioAB]

Greetings,

I see my AVI/DivX or MKV/H264 movies played with Media Player Classic going constantly out of sync regard A/V.

My reference is DVD (the old and good DVD).
I understand it uses the MPEG TS container that assure A/V synchronization by means of TIMESTAMPS.

I know the AVI container does not have timestamps but I had expectations that Matroska MKV had it.

Can someone confirm MKV does not have timestamps ?
Does MKV/H264 constantly goes out of sync ?
Is there a container for H264 that can handle timestamps ?
Will that resolve my issue of out of sync ?

Sorry so many questions but I was looking a long time over here for such answers and could not find them.


:thanks:
Marcio

[foxyshadis]

DVD -> mpeg PS, not TS, though both have timestamps.
MKV -> Yes, they have timestamps, a quick look at the specs would show you.
MKV/h.264 -> Of course not, or no one would use them.
Container -> mpeg, ts, mkv, mp4, wmv, probably others.
Sync -> Probably not. You can screw up the muxing no matter what format you choose, which might be what this all comes down to.

Are you playing on a 700MHz Celeron or something else woefully underpowered? H.264 is pretty cpu-heavy after all. If cpu is holding at 100%, you'll never have a pleasant viewing experience. There are 3 ways it can be handled: Slow down the video, slow down+chop up audio, or drop frames until the next I-frame. The first causes desync, which seeking will usually fix, the second causes stutter, and the third stops showing video often.

If you hate the current behavior, you need a different splitter. Haali's uses the second method, and I thought gabest's (MPC) used the second as well, but it could be the first.

If you're not at 100%, then your files are just muxed wrong and you'll have to fix that.

[setarip_old]

I see my AVI/DivX or MKV/H264 movies played with Media Player Classic going constantly out of sync regard A/V.It's hard to conceive of virtually ANY system being inadequate to properly process a DivX-compressed .AVI.

1) What software and procedures are you using to create the .AVI?

2) Does the original source material (used to create the .AVI) play properly on your PC?

3) have you tried playing the videos with other software players?

[mdoubledragon]

Good Day!
I have had many out of sync issues in the past too. I searched many forums but in the end I found out that encoded output of some DVDs I have is always out of sync whether I use commercial or non-commercial encoders (In my case it was Patch Adams).
So I found out a new way to watch my backup media. Mplayer does a fantastic job of keeping the video and audio in sync (perhaps by checking their lengths and trying to fix the overlap). In some movies I encoded, the audio video sync delay was a constant (say 100ms) but in some it kept changing with every chapter. If MPlayer does not automatically take care of things, you can always command it to set an appropriate A/V delay.
Now thats just a way to play something you waited many hours to encode. If you want the output to be perfect, maybe some guru can help you with that.:helpful:

[MarcioAB]

Are you playing on a 700MHz Celeron or something else woefully underpowered?

CPU is AMD64 3700+
Memory is 2G DDR at 400Mhz (dual)
HardDisk 1 is WD Raptor 10000 rpm.
HardDisk 2 is 2x250GB 7200 rpm RAID 0
Video Card is nVidia 6600 512MB with 2 screens: desktop 20' CRT at 1280x1024 and extended to Sony Bravia HDTV at 1280x768 (HDTV itself is 1366x768).

Using MS GraphEdit and displaying the video on HDTV with SetClock=off (so CPU at 100%) I can deliver minimum 48 fps (the movie is 24 fps).
With SetClock=on the 24 fps can be delivered with CPU at 44% load.

So, I do not think "horse power" is the problem.

If you hate the current behavior, you need a different splitter. Haali's uses the second method, and I thought gabest's (MPC) used the second as well, but it could be the first.

The splitter is already Haali (the container is MKV). Double checked using MS GraphEdit.
But I did not follow exactly: Is Haali good or bad ?

If you're not at 100%, then your files are just muxed wrong and you'll have to fix that.

The movie (Lost episode 17 at HD definition) download from internet. I am assuming it was well done and without A/V sync issues (still need to double check that).


MKV -> Yes, they have timestamps, a quick look at the specs would show you.
MKV/h.264 -> Of course not, or no one would use them.
Not follow this. I'm looking for something on the HD land with enforced A/V sync by means of timestamps like the old DVD. I understood you said MKV (Matroska) container have timestamps so I expect it should be used in each header of the video streams and the audio streams to enforce sync.
Then you say MKV container with h.264 video stream do not have (or do not use) timestamps ... I do not understand and I would really appreciate if you could explain that a little bit.

:thanks:
Regards
Marcio

[MarcioAB]

1) What software and procedures are you using to create the .AVI?
In these cases I'm downloading from Internet some TV episodes in Standard Definition (603x336 @ 24 fps) and some in near HD (960x535 @ 24 fps).
I'm considering they are free of A/V sync but I'm realizing I need to double check. But it will be a disappointment is all those episodes have A/V sync issues.

2) Does the original source material (used to create the .AVI) play properly on your PC?
The PC is a kind of HTPC. The HDTV is connect in the Graphics Card and it can handle 2 monitor, the principal CRT like any PC and an extended Windows work area using the HDTV.[/QUOTE]

3) have you tried playing the videos with other software players?
No. Need to try that. Any sw players suggested ?

:thanks:
Regards
Marcio

[MarcioAB]

Good Day!
If you want the output to be perfect, maybe some guru can help you with that.

Good day.
Yes. I want that perfect and I also hope those gurus can help me and someday I can help someone else.

:thanks:
Regards
Marcio

[foxyshadis]

Not follow this. I'm looking for something on the HD land with enforced A/V sync by means of timestamps like the old DVD. I understood you said MKV (Matroska) container have timestamps so I expect it should be used in each header of the video streams and the audio streams to enforce sync.
Then you say MKV container with h.264 video stream do not have (or do not use) timestamps ... I do not understand and I would really appreciate if you could explain that a little bit.

"Of course not, or no one would use them." was a reply to "Does MKV/H264 constantly goes out of sync ?" I thought having them in order would be clear enough.

Anyway, this forum does not condone or help with downloaded video; rule 6 is one of the most often brought-up rules so you should be familiar. Anything can be the problem when you have no idea how they were ripped/muxed, and in this case it was most likely done wrong.

(Possible solution to internet piracy, even beyond MediaDefender's (http://arstechnica.com/articles/culture/mediadefender.ars) methods: Pollute torrent sites with off-sync, low-quality encodes with multiple stream errors. Hah!)