I have used Myth to rip a large number of my DVD's to AVI files (using either the Excellent or Good setting). Now that I am starting to play back the movies, I have found something that is very troubling.
On many of the movies, the first 95% of the movie (e.g. 1:13 min of a 1:26 movie) plays flawlessly. However, near the end of the movie, the audio and video starts to speed up and get jerky. (Audio/video sync is also thrown off.)
I have copied the files to a different box and played them with totem and mplayer and was happy to find that the files appear to be just fine. (or maybe mplayer/totem deal with them better?)
It seems that the problem is with the mythv internal video player.
After a random sample of movies, I'd say that at least 50-70% (but not all!) of the movies have this problem. The problem survives reboots of the mythtv box.
I am using Xvmc for HDTV playback (with no problems), (OSD is B&W) but not for the internal video player. (OSD is in full color)
Even if I ESC from the movie and then go back into it (the internal player resumes at the same spot) the problems continue as before. If I rewind the movie, it works correctly before the "problem starting spot" but when it hits that spot, the problems resume.
I suspect it may be a problem that is caused by the MythTV ripping system, as I have re-encoded movies using mencoder that then play back correctly in the internal video player.
I was able to solve this problem (which appears to be a problem in the index of the avi files generated by MythDVD) by using mencoder to re-create the index for all of my video files.
mencoder -idx MOVIE_TO_FIX.avi -ovc copy -oac copy -o FIXED_OUTPUT.avi
I created the following script to go through my video files and re-create the index (it takes about a minute per movie). The script will only process a movie one time (keeping track by creating a marker file in the hidden .fixed_list directory) so it's safe to run every time you rip new DVD's without repeating work needlessly:
#!/bin/bash for movie in *
do
if [ -f ".fixed_list/$movie.fixed" ]
then
echo "$movie already fixed"
else
echo "Processing $movie"
mencoder -idx "$movie" -ovc copy -oac copy -o temp_file.avi
mv temp_file.avi "$movie"
touch ".fixed_list/$movie.fixed"
fi
done
Movies with a problem generated the following message when re-creating the index:
ODML: Starting new RIFF chunk at 1023MB.m:
I'm not sure what a new RIFF chunk is, but apparently the built in MythDVD encoder is not producing them correctly.
2 Comments
How do you adjust this for VOB files? I tried your mencoder command on a single ripped VOB file and it took out all of the so called duplicate frames. I have tried several options (-vf harddup, -fps) but can’t seem to find the right set of switches.
BTW. I am not sure if we have the same problem. I ripped these files with DVD Shrink through Wine into a single VOB per show/movie. Some play fine and some don’t through the internal player. The ones that don’t play correctly have this index problem.
FYI. I have 2 boxes. The front box is a box purchased by the now dead TVEase. The back box is a server with currently 3.41 TB of storage. Both run Ubuntu and MythTV. Shared files are mounted via NFS.
Wayne,
I’m not sure if mencoder will read/write to VOB files. You may have to extract the video, re-index it, and then put it back into the VOB file.
Jay
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