brandonj
2008-02-28, 06:35
I have some videos encoded into and MP4 container using the H.264(High Profile)/AAC ccodecs. I noticed that when playing back some of them, XBMC shows the video very distorted (it actually looks a lot like scrambled analog cable from back in the day). Subtitles are displayed, and the audio sounds fine. I tried to dig a little deeper, and determined that XBMC doesn't like the subtitles.
I used MP4Box to create a new mp4 file with the A/V streams taken from the "broken" file, and played that back and it worked fine. I then created another MP4 file using the same streams, and included the subtitles back in to the mix. I got the distorted video again. I also noticed that when I start to play one of these files, it takes a few seconds longer to start playing the file (i even get the buffering dialog while it waits).
I realize that VOBsubs are not MP4 standard, and probably shouldn't be in there to begin with, but some players/libraries (FFMPEG included) will still use them as Nero hoped they would when they decided to implement this feature.
I first noticed this problem when the whole dual-core decoding of mp4 files was added a few days ago, but it may have started before that, but just haven't been playing mp4s for a while.
I am not knowledgeable enough to fix the problem myself, but I would like to help in any way I can to resolve this problem, if anyone is willing. I could even provide some sample files for proof of concept if needed.
-Brandon
(Athlon 5600+ X2, 2GB RAM, GeForce7300GT, Ubuntu Gutsy Gibbon)
I used MP4Box to create a new mp4 file with the A/V streams taken from the "broken" file, and played that back and it worked fine. I then created another MP4 file using the same streams, and included the subtitles back in to the mix. I got the distorted video again. I also noticed that when I start to play one of these files, it takes a few seconds longer to start playing the file (i even get the buffering dialog while it waits).
I realize that VOBsubs are not MP4 standard, and probably shouldn't be in there to begin with, but some players/libraries (FFMPEG included) will still use them as Nero hoped they would when they decided to implement this feature.
I first noticed this problem when the whole dual-core decoding of mp4 files was added a few days ago, but it may have started before that, but just haven't been playing mp4s for a while.
I am not knowledgeable enough to fix the problem myself, but I would like to help in any way I can to resolve this problem, if anyone is willing. I could even provide some sample files for proof of concept if needed.
-Brandon
(Athlon 5600+ X2, 2GB RAM, GeForce7300GT, Ubuntu Gutsy Gibbon)