idx subtitles + 2 pass

[hazard]

Ok, first I think I need to explain where this is coming from.

I've been using ffmpegx to make files that are to be merged into mkvs (with the commandline tool mkvmerge) (for no specific reason other than curiousity and random intrest). I've been using alot of the older versions of the binaries (version k I think), the last one I was aware of that allowed you to copy and paste the mencoder command to a text file (so I could see what it was doing, and have an easier time making batch conversions with termical etc). I use ffmpegx 0.0.9s on my tower to do some of the video convesion work (because mpeg4 encoding in 9s is faster I think).

Now, my seemingly arbitrary goal was to was to have a file that had select able subtitles and audio.

The problem was that when I did a two pass encoding (in either 0.0.9s or k), using the .idx sub setting then did the merge, the player (VLC) would ALWAYS crash at some random point into the movie, which wasn't helpful towards my goal. Additonally unless I told mkvmerge to only merge in track 0 of the idx sub file it would give me two identical subtitle tracks (both en or whatever language track I selected) in the output file (which was just annoying more than anything, and telling mkvmerge to use only the first track, track 0, made it only one, but it still crashed).

Because the .idx file is a text file, I opened it with textedit, and noticed that the subtitle timings were entered twice into the file (identically). Deleting one copy made it so I didn't need to specify a track number to mkvmerge.

I don't know what made me notice, but when I was playing with one of the encoding settings I got from 0.0.9k's progress window info button, I found that if I deleted one of the "-sid x -vobsubout [file]" (or I think that's what it was) it not only dropped the size of the .sub and .idx files in half, but when I merged the file, it no longer made the player crash at random intervals into the movie (always the same time for any given clip that exhibited the random crashing problem).

What I THINK I've concluded, is that subtitles are extracted using the idx setting in 2 pass mode, then the subtitles are extraced twice into the same files (appended to the ones made in the first pass).

If then merged into an mkv file (I have no idea if this applies to files/processes other than mkv, as that's the only thing I've been playing with), then these dual-copy files crash the player (or at least VLC).

HOWEVER, if I extract the subtitles in single pass mode with mencoder (say perhaps when I'm grabbing the other audio track using the "-ovc frameno" setting) from the command line, then the problem isn't there and everything is peachy.

I guess, my point is, that dual passing avi /w extracted .idx subs=corrupted subfiles (at least for mergeing into an MKV file). If the "-vobsubout" line is removed from either of the passes, then it dosen't happen (I think, the problem seems completely arbitrary in the first place-however, now that I've been looking for it, it has explianed every problem with all the DVD's I've tried it with, at least the subtitle track problems).

I'm almost certian that I'm the only one on the planet that will experience this problem (while playing with encoders no less!) - but it could come up, and since I don't know if this could possibly affect anyone else (as I don't know what else to do with a .idx/.sub pair), I figured it couldn't hurt to mention.

[major]

Thank you for your report. I add it to my to-do list for further cleaning & fix.