ffmpegX - idx/sub subtitles lost in converting from avi to Xvid or DivX

[bonespur]

I'm using ffmegX v0.0.9y (on an Intel iMac) to convert two sets of files (avi + idx + sub) into Xvid or DivX files.

The main problem is that the idx/sub subtitles are not making it through the conversion and into the Xvid and DivX files that I've managed to create to date using ffmepX.
For reference, note that when I converted the same source files into mpg files using ffmpegX, the subtitles did come through the conversion process fine.

A lesser problem is that there is a constant 0.5-s audio-video sync offset in the Xvid and DivX files that I've managed to create to date using ffmpegX.
While I can eliminate that audio-video offset using QTSync, I'd like to know how I can avoid the sync offset altogether in the conversion process by ffmpegX.

[Case]

avi + idx + sub to Xvid or DivX. The subtitles are not making it through the conversion.

This is a known limitation of the software. Most conversion types with ffmpegX do not allow VobSub.

When I converted the same source files into mpg files, the subtitles did come through.

This is a known exception of the above, together with MKV with embedded VobSub. Going avi + idx + sub > MKV > XviD mencoder is the way to deal with this, if no matching .srt can be found.

There may be another way of burning VobSub onto the video: Perian. If you set ffmpegX to use QuickTime as decoder, then QuickTime may call upon Perian to insert the subtitles into the frames that are served to ffmpeg while encoding. This way ffmpegX doesn't have to be told about the subs.
Testing playback in QuickTime Player, of the source file with the subs in the same folder, should tell you if Perian picks up on the subtitles.

A lesser problem is that there is a constant 0.5-s audio-video sync offset in the Xvid and DivX files that I've managed to create to date using ffmpegX.

This might be caused by a sync offset of one stream in the source file. Or some other reason.

I'd like to know how I can avoid the sync offset altogether in the conversion process by ffmpegX.

Using 'Decode with QT' seems to solve some of the sync issues with my files, but that option isn't available when burning in subtitles through ffmpegX, as that normally requires mplayer decoding.

[bonespur]

Sorry to report I haven't found the way yet.

This is a known exception of the above, together with MKV with embedded VobSub. Going avi + idx + sub > MKV > XviD mencoder is the way to deal with this, if no matching .srt can be found.

Unfortunately, I haven't found a way to install MKV into my iMac (Intel), which is running OS X 10.4.11.
The posting that you referred to

the way to deal with this

led me to MacPorts.org. from whence I downloaded MacPorts and then attempted to install it. However, I found that to do so one requirement is that my system should include Xcode - which then I tried to install (from the Apple Developer site, as directed by MacPorts.org). I found, however, that I could not install Xcode because installation of the available version of Xcode requires OS X 10.6.
Also, though MacPorts.org referred to some available older binaries for MacPorts, none of the three of them would open in OS X 10.4.11.

There may be another way of burning VobSub onto the video: Perian. If you set ffmpegX to use QuickTime as decoder, then QuickTime may call upon Perian to insert the subtitles into the frames that are served to ffmpeg while encoding. This way ffmpegX doesn't have to be told about the subs.
Testing playback in QuickTime Player, of the source file with the subs in the same folder, should tell you if Perian picks up on the subtitles.

I installed Perian about a week ago, in the process of trying and succeeding to get QuickTIme to display the subtitles from the idx & sub files. Consequently, when I began trying to convert from (avi + idx + sb) to xVid/DivX using ffmepgX with "Decode with QT" selected, I half expected the subtitles to show up OK in the outputted Xvid/DivX files. However, after I do select "Decode with QT" (in ffmpegX/Options), then convert, and then play the outputted Xvid/DivX files, the video freezes while the audio plays.

Using 'Decode with QT' seems to solve some of the sync issues with my files, but that option isn't available when burning in subtitles through ffmpegX, as that normally requires mplayer decoding.

Actually, as indicated above, I found that "Decode with QT" is an available option when converting from avi to Xvid/DivX through ffmpegX. I found it's not an available option when burning through mencoder. Did I misunderstand here?

[Case]

iMac (Intel), OS X 10.4.11.

MkvMerge is also the name of the GUI part of MKVToolnix-2.3.zip (8.7 MB) for Mac OS X 10.4.11. You do not have to build it yourself through MacPorts.
(More recent versions of pre-build MKVToolNix Mac GUI require Leopard (10.5)/Snow Leopard (10.6).)

However, after I do select "Decode with QT" (in ffmpegX/Options), then convert, and then play the outputted Xvid/DivX files, the video freezes while the audio plays.

Sorry to hear that. Not sure why that would happen.

Actually, as indicated above, I found that "Decode with QT" is an available option when converting from avi to Xvid/DivX through ffmpegX. I found it's not an available option when burning through mencoder. Did I misunderstand here?

You understood correctly. XviD mencoder uses mplayer for decoding; and XviD ffmpeg uses ffmpeg or QuickTime for decoding.

[bonespur]

I'm making progress - thanks to you, Case.
I'm still having a problem with the second part of the process, which involves ffmpegX.

Here's what went fairly well, apparently

MkvMerge is also the name of the GUI part of MKVToolnix-2.3.zip (8.7 MB) for Mac OS X 10.4.11.

The third of the three files there opened up (the other two wouldn't) and I was able to install MkvMerge.

I didn't see specific instructions in the MKV Help file for how to handle (avi + idx + sub).
Nevertheless, in test runs of MkvMerge, I was able to load the avi and idx files under the "Input" tab - and so I did. Also, I was able to load the sub file under the "Attachments" tab. After some casting around on the web, I found an indication that the correct MIME type to enter along with the sub files might be "application/x-truetype-font" - so that's what I entered under there. Is that correct?
Then I clicked on "Start Muxing".

Whereas the outputted file I produced from the first set of (avi + idx + sub) source files was an mkv file, the outputted file from the second set of (avi + idx + sub) files was an mks file. I don't know the reason for the difference in file types.

Both outputted files play fine in VLC Player - showing the subtitles, and with no loss of audio-video sync.
[by the way, is it significant that when I play the same files in DivX Player the subtitles are missing?]

Here's the remaining problem
I converted the mkv file to avi XviD using ffmpegX with mencoder.
In ffmpegX/Options, I checked the box for Vob Subtitles, and not knowing any different I selected 0 and idx in the adjacent boxes; and I did not load any subs into the box below.
ffmpegX outputted three files: mkv.ff.avi, mkv.ff.avi,idx, and mkv.ff.avi.sub.
When I launch the outpuuted mkv.ff.avi file in VLC Player, only the audio plays - NO VIDEO.

By the way, do the following default specs - which are displayed in the "To" window in ffmpegX/Summary/Target look right to you?
mencoder xvid, 640x352, 4 kbps, 0.08 fps, no crop
While I'm hardly at all video cognizant, 4 kbs and 0.08 fps seem to be low settings to me.

[bonespur]

I have found out a way to successfully convert my mkv files to avi XviD using ffmpegX with mencoder.
Here's a brief summary, in case it helps someone else convert from mkv to XviD using ffmpegX.

I had to change some of the settings that seemed to pop up by default when I loaded the my source mkv file into ffmpegX.

[By the way, it helped that I slowed down and I read a little more of the nicely written documentation about the settings in the tabs in ffmpegX. Starting with the documentation page for the Summary tab, at http://ffmpegx.com/summary.html . Reading the documentation was a bit of a struggle, as I'm not video as video savvy as most writers in this forum - but nevertheless the reading helped.]

Here is a summary of the settings that I had to change in ffmpegX (after I loaded the source mkv file into the box adjacent to "Open"), in order to get a good conversion from mkv to Xvid.

In ffmpegX/Video/Bitrate Calculator
- I clicked the "Rate" button (In the case of the files that I was converting, that increased the bitrate from 4 kbit/s (which had seemed to appear by default) to 1881 kbit/s).

In ffmpegX/Video/Video parameters/Framerate
- I selected NTSC (29.97) (In the case of the files that I was converting, that increased the framerate from 0.08 fps (which had seemed to appear by default) to NTSC (29.97).

In ffmpegX/Filters
- I checked the box for VOB subtitles.
- I left the 0 in the adjacent box.
[I'm still confused about why I should have needed to do the following two steps, because I thought I had already burned the subtitles into the intermediate mkv files using MkvMerge.]
- I selected Burn in the next adjacent box, as my objective was to "burn" the subtitles into the outputted XviD files (in contrast to the soft idx/sub subtitles in the original, source avi+idx+sub files).
- In the box adjacent to "Load subs" I entered the idx file from the original set of avi+idx+sub files.

In ffmpegX/Options/mencoder XviD options.
- I checked all the boxes except for Cartoon content (because the files contained no cartoons).
[In prior test runs, I didn't check those boxes; and the resulting outputted video was of low quality.]

By the way, also at one point it seemed to help to change the mks extension of the second of my two Matroska files to mkv from mks.

Based on a brief inspection, the video quality of the outputted XviD file looks only slightly less than that of the source avi file.