picture from VCDx + audio from VCDy

[headless chicken]

OK, I'm going to need quite a bit of help and direction with this little project of mine. :P

I have 2 VCDs of the same film in two different languages, Hindi and Telugu. The Telugu language is unintelligible to me, but this version has better quality picture, though the colors are oversaturated. Thus, I want to use the Telugu picture with the Hindi audio and output to the best possible quality I can.

1. Resize?
A VCD's native resolution is 320x240. However, if I am going to be re-encoding the picture to fix the oversaturation, I would like to resize to 448x336 (I ripped the prequel at this resolution). With some sharpening filters, the picture shouldn't look too bad, right?

2. Format:
I've been lead to believe an AVI container with XviD codec is one of the best options in terms of picture quality and compression. Which would result in the least data loss; converting to AVI to two 700MB files, or sticking with MPEG? And if the latter is preferable, what video option should I select in avidemux (ie. Mjpeg, mpeg4, meg2 requant, etc.)? I see on option for MPEG video format, but I'm sure I can't select some conflicting codec like xvid, right? (AVI dual audio...ooh, that's interesting...maybe I should explore that)

3. Audio:
Both the Hindi and Telugu feature span 2 discs each. However, they're split at different places. Moreover, the Hindi version is further split into two different dat files on each disc (so the total feature spans four DAT files).

To complicate things further, the opening credits are not identical and one version runs a minute longer. Luckily, the Hindi credits are in their own little DAT file/MPEG. Thus, I could copy this whole file and tack it on to the beginning of the Telugu picture, part1.


Here's my thought process:
--> extract MPEG from DAT with Gumby
--> join all four Hindi MPEG files into one composite
--> cut between AVSEQ02.mpg and AVSEQ03.mpg (a few seconds are repeated)
--> demux and save the audio to AIFF.
--> clean Hindi audio with SoundSoap
--> merge Hindi title sequence with Telugu mpg1
--> convert/re-encode if desired
--> add Hindi audio track
--> repeat process with Telugu mpg2

Is this the best way to proceed?

Unresolved Issues:
A. I need a program which will allow me to
(1) merge audio and video while previewing the result to solve any potential sync/time delay issues? D-Vision allows you to re-encode audio to a file or add a different track, but there’s no preview. Avidemux gives me very choppy playback if audio is enabled in preferences, plus there’s no way to timeshift as far as I know.
(2) select start and end points with the AIFF made from the combined Hindi mpg so the audio begins at the correct place in part 2

B. When is the optimal time to demux; before merging the mpgs (merge m2v’s instead), or after?

I know this was probably confusing, but I would be so grateful for some guidance. I love this film dearly (moreso it’s prequel—that’s another story), and hopefully one day it will get a decent DVD release by a reputable Indian distributor (of which there are very very few), but until then this is my best bet for archiving this film. :P

[Cornucopia]

VCDs, right?

What do you want to end up with? DivX/Xvid? another VCD? DVD? Something else entirely?

Let's assume you want DivX/Xvid, because you are only going to play via a PC or you have a DivX-capable deck...

Rip with VCDEasy (VCDxRip tool) or VCDGear (DAT->MPEG).
Open each MPEG in Virtualdub (Full processing for both A + V). Save as losslessly compress Vid + lpcm WAV.
Concatenate(merge) the segements so you have 2 full-length versions.
Compare the versions with a video editor, lining them up to make sure they match PERFECTLY in sync and in length.
(If they don't, cut the longer of the 2 down to the size of the shorter).
Export to DivX.

Scott

[headless chicken]

Virtualdub may be great for PC, but I'm running Mac OS X with no intention of installing Windows on my system.

And yes, I've got a nice, upconverting standalone DivX player, but I'm just looking for the format which will give me the best quality.

[Cornucopia]

Best of luck to you then. You're at a SEVERE disadvantage WRT working with VCDs(though there is a VCDGear for OSX) and Windows AVI (DivX or no). I'll let others give some suggestions...

Scott

[tomlee59]

If your goal is to obtain the highest quality result, starting from VCD source material, you're better off not transcoding (but I don't know if you can fix your color problems without doing a "real" transcode). Every transcode results in degradation. VCD isn't all that great to start with, so you can't really afford to make things worse by transcoding. That said, there might be other motivations for conversion, such as greater availability of editing tools, etc. If that's the case, then transcode with the highest bitrate consistent with your filesize/disc capacity limitations. But if quality of the end result is your primary concern, minimize the number of conversions (and zero is the theoretical minimum)

So, stick to demuxing/remuxing and splicing/merging to preserve what you've got. If you're planning to keep things in VCD format (even if you're eventually going to burn them as DVD), you'll want to use tools like VCDgear, (More)Missing Mpeg Tools, MPEGStreamclip and ffmpegx.

[Cornucopia]

I didn't mention the demuxing/remuxing route, because frankly, in 99 times out of 100 where you have 2 different shows and are trying to swap better streams (like you are), you're going to have to edit at a finer resolution than a GOP, and that means re-encoding.
If you're going to re-encode, might as well do it right.

Scott

[headless chicken]

If your goal is to obtain the highest quality result, starting from VCD source material, you're better off not transcoding

Yes, I understand this point completely. I wouldn't even consider transcoding if the colors weren't so garish and neon, but maybe I'll just make do with neon orange faces, hot pink and glowing yellow hues.

Perhaps this project was a bit too ambitious, because I'm having problems almost every step of the way beginning with merging the MPEGs. I joined the MPGs as per the instructions here. I used MPEG Streamclip because unlike other applications, it managed to merge the files without giving me a pixelated transition with a blipping noise between the two.

However, the output file is actually *smaller* than one of the two files I joined! It should be 15 MB files larger (because the smaller of the two files is 15MB). What's going on? Is MPEG Streamclip compressing my file?? Or is it deleting 16MB worth of headers? This doesn't make sense. What's happening to the missing data? Moreover, the time of the resulting file does not add up.

What I really need is a tool that will allow me to view the video stream while adding a new audio track. I never thought to invest in Final Cut Pro, but I suspect it might have this feature set.

What's really distressing is that the video and audio are slightly different times (16 seconds or so), with the audio being longer. It's probably due to the video editing I had to do to extract the audio, because I deleted a few seconds here and there that were repeated between the two discs, and I suspect MPEG Streamclip ate up some seconds on it's own. Gaah!

How can I offset the audio? It seems to be off by a second or so...

[tomlee59]

I don't know about the specifics in your case, but here are some problems I have encountered when trying to do similar things, and what I did to make them work in the end. You've probably tried many of these already, so I apologize if they're redundant.

1) When using MPEGStreamclip to merge files, be sure to use the "fix timecode breaks" command and save the result. Not doing this can frequently cause duration problems of the sort you've mentioned.

2) Merge only at keyframe boundaries (it sounds like you did this successfully). Failing to do so can cause data breaks that also may truncate playback/reduce filesize (by simply omitting data after the break).

If the result has a constant sync error, demux, then remux using, eg., ffmpegx, which allows you to specify a time delay/advance to fix this problem. I use VLC's sync offset capability to zero in on the correct number (check the playback sync at beginning, middle and end to be sure you've picked a good value), and then plug the *negative* of that number into ffmpegx.

If the sync has drift in addition to offset, you can use a tool like Audacity (free!) to stretch or compress the duration of the audio. The Tempo change command is ideal for this. Since the corrections are typically very small, percentage-wise, you will not notice any pitch changes. A combination of offset and drift correction takes care of the most common sync problems.

If the sync changes abruptly (very common at scene changes, where there are several blank frames), you may have to separately resync the segments on both sides of the break, then re-splice those pieces.

I hope some of this helps. Good luck!

[headless chicken]

Tomlee, thanks for your suggestions. They are very insightful.

1) When using MPEGStreamclip to merge files, be sure to use the "fix timecode breaks" command and save the result. Not doing this can frequently cause duration problems of the sort you've mentioned.

I wasn't doing this priorly because even after fixing time code breaks, when I would save the result, MPEG Streamclip would report that there were breaks in the saved file.

2) Merge only at keyframe boundaries (it sounds like you did this successfully). Failing to do so can cause data breaks that also may truncate playback/reduce filesize (by simply omitting data after the break).

It seems as though in most cases, the very first frame of a file is often indexed as a keyframe. To merge the mpgs, I have been going in sequential order, opening the first file, copying it, opening the second file and then pasting directly into it. Next, I cut the redundant selection after locating the keyframes. However, I've never been sure whether to cut at the actual keyframe, or one before it.

MPEG Streamclip is a bit tricky because if I merge the files starting from the last to the first or in any other order, only a few minutes worth of footage will appear in the preview window.

If the result has a constant sync error, demux, then remux using, eg., ffmpegx, which allows you to specify a time delay/advance to fix this problem. I use VLC's sync offset capability to zero in on the correct number (check the playback sync at beginning, middle and end to be sure you've picked a good value), and then plug the *negative* of that number into ffmpegx.

Regarding the time sync, I found the first few minutes are perfectly in sync, as is a dance number about half way through the film. In between, the audio is off by varying times. I was wondering why the two files differed in duration by 15 seconds, so I began playback of the m2v and mpeg (with desired audio). I found that in one particular scene, a shot lingers an extra second. I suspect there are several such differences between the two files. Thus, this does not appear to be a typical sync problem but a more complex one with the audio and video in synch in some scenes, but not in others.

I tried playing the m2v in Streamclip (the corresponding AIFF loads automatically, athough it's longer), and the audio is really out of synch. I noticed Streamclip shows the file duration as the longer of the two (audio). However, if I play the m2v and AIFF side by side in QT with a delay of less than one second, everything synchs up perfectly for the first 20 minutes, and then there were some drift issues. I suppose there is no alternative but to manually synch each scene or section, right?

I'm about to try the timestrech option you suggested.

[headless chicken]

OK, the time stretching (or shrinking in this case) option did not work. It's going to take a bit more tinkering than entering a value to offset by, since the audio syncs with video in the beginning and part of the middle, but not in other places. It looks like I will have to offset or stretch/shrink/delay on a scene by scene basis. Is there some powerful video/audio editor that will allow me to do this?