Log in

View Full Version : Windows Media Player 12 Can't Seek properly with AVC(+AAC in MP4)?


DeathTheSheep
18th April 2010, 06:13
Hey guys. Long time no see.
Anyway, this is very strange. After following a discussion here (http://forum.xda-developers.com/showpost.php?p=6127563&postcount=72) for a while (yes, I also got one of those silly phones), I found that the test clip (http://www.mediafire.com/file/tkml3ofmyjo/lag7.mp4) (baseline, 1 ref AVC file with a CBR AAC-LC stream) plays fine in Windows Media Player 12 (the one with built in codecs/splitters) UNTIL I tried seeking into the file. It then goes out of sync, never to recover.

Intrigued that the same problem on my new phone should happen on my desktop, I tried some similar x264+nero AAC files muxed with MP4box and tried them out--same result. Same files (all of them) play fine in VLC and the like. Strange to think the most abundant media player in the world has such a glaring and frightening flaw. Maybe this is also the reason behind the "desync" these folks are talking about for their Windows Mobile phones (also using Windows Media Player).

What do you think? Can anyone replicate this? Could it be the container/audio fault? Note that I tried mp4box versions from 0.4.3 to 0.4.6-dev (that's from 2006 to 2009). I also tried with faac and divx audio encoders, so I doubt it's the audio. I didn't have time to try different AVC encoders (don't know of any real "competition"), but for my tests the --profile baseline --preset veryslow with --crf 23 produced the same issue in my files. Any thoughts?

wlee15
18th April 2010, 10:38
Works perfectly fine on my Windows 7 64-bit using the default 32-bit WMP 12 player.

DeathTheSheep
18th April 2010, 23:37
Maybe it's just my quirky system then. But...

Are you sure it's not 150ms or so out of sync? It only appears when seeking. Try seeking a few seconds before the end. In my system the beeps play exactly when the screen shows "nothing."