pwnsweet
14th May 2011, 14:26
Hi,
I'll try to keep this short. I've been encoding Blu-ray movies to H.264/AVC mp4 format. Of the movies I've done so far, they all work fine. But recently I encoded Mission Impossible 1, 2 and 3 and have had problems with all three of them. When I encode these movies, the audio is out of sync with the video. Here is the procedure I follow when trying to encode these movies:
1. Copy the .m2ts movie file from the BD to my HDD
2. Use MeGUI to extract the 5.1 .ac3 audio track from the .m2ts
3. Use AVS script creator to open the .m2ts file I copied earlier to my HDD to create my avs script and load it into MeGUI
4. Open the 5.1 .ac3 audio file I extracted earlier in MeGUI
5. Queue the job, encode audio, encode video, mux.
The result is audio and video desynchronization in my encoded video file. The following behavior is the same with all three movies. Initially the video and the audio will be synchronized. As the movie progresses, at certain points in the movie (different locations for each movie) the audio will become desynchronized by a fixed amount and continue to be desynchronized by the same amount until the next point in the film where it will desynchronize even more. It is not a problem where the audio continuously becomes more and more desynchronized as you would find when the video frame rate does not match that of the audio. This is different, and occurs at discrete locations throughout the movie.
Now, I've done some testing myself to try and find where the problem lies and have found the following:
1. The problem is almost certainly related to the video stream. I've confirmed this by extracting the video stream from the source .m2ts file (where the audio and video are obviously synchronized) and then muxed my encoded audio to the source video stream and the video and audio are in sync the whole way through the movie.
2. In addition to the above, I've also noticed that at the points in the movie where the audio and video begin to desync and then again at the points where the desyncing gets worse, the encoded video exhibits pixelation like you would see when watching a badly scratched DVD. What I find unusual about this is that at the same location in the source video, no such pixelation is seen.
3. And finally, I noticed that all 3 Mission Impossible movies are the first movies I've tried to encode that have an MPEG-2 source stream. All the other movies I've done so far (without any issues) have been H.264/VC-1.
And so far that's all I've managed to figure out. Could the problem be with the decoder I'm using (libmpeg2)? If so, which decoder would you recommend? Or is it more likely a problem with x264 or something else? Would love to hear your thoughts.
I'll try to keep this short. I've been encoding Blu-ray movies to H.264/AVC mp4 format. Of the movies I've done so far, they all work fine. But recently I encoded Mission Impossible 1, 2 and 3 and have had problems with all three of them. When I encode these movies, the audio is out of sync with the video. Here is the procedure I follow when trying to encode these movies:
1. Copy the .m2ts movie file from the BD to my HDD
2. Use MeGUI to extract the 5.1 .ac3 audio track from the .m2ts
3. Use AVS script creator to open the .m2ts file I copied earlier to my HDD to create my avs script and load it into MeGUI
4. Open the 5.1 .ac3 audio file I extracted earlier in MeGUI
5. Queue the job, encode audio, encode video, mux.
The result is audio and video desynchronization in my encoded video file. The following behavior is the same with all three movies. Initially the video and the audio will be synchronized. As the movie progresses, at certain points in the movie (different locations for each movie) the audio will become desynchronized by a fixed amount and continue to be desynchronized by the same amount until the next point in the film where it will desynchronize even more. It is not a problem where the audio continuously becomes more and more desynchronized as you would find when the video frame rate does not match that of the audio. This is different, and occurs at discrete locations throughout the movie.
Now, I've done some testing myself to try and find where the problem lies and have found the following:
1. The problem is almost certainly related to the video stream. I've confirmed this by extracting the video stream from the source .m2ts file (where the audio and video are obviously synchronized) and then muxed my encoded audio to the source video stream and the video and audio are in sync the whole way through the movie.
2. In addition to the above, I've also noticed that at the points in the movie where the audio and video begin to desync and then again at the points where the desyncing gets worse, the encoded video exhibits pixelation like you would see when watching a badly scratched DVD. What I find unusual about this is that at the same location in the source video, no such pixelation is seen.
3. And finally, I noticed that all 3 Mission Impossible movies are the first movies I've tried to encode that have an MPEG-2 source stream. All the other movies I've done so far (without any issues) have been H.264/VC-1.
And so far that's all I've managed to figure out. Could the problem be with the decoder I'm using (libmpeg2)? If so, which decoder would you recommend? Or is it more likely a problem with x264 or something else? Would love to hear your thoughts.