DivX to SVCD, encoding error with VirtualDub

[lichtgestalt]

Hi guys!

I've been converting around 60 Buffy episodes from PAL-DVD to SVCD with no problems, so I'm familiar with the different tools. Now I try for the first time to convert some (NTSC?)-DivX to PAL-SVCDs. I read a few FAQs and guides, but still...
Could anyone tell me if my approach is correct:

1. I open the DivX in VirtualDub and scan for bad frames (assuming none were found). I correct any a/v sync problems or non-standard framerate issues of the source material.
2. I save the audio track as WAV (assuming the DivX has the correct 23.970 fps).
3. I re-encode the video to resize to PAL-SVCD's 480x576, crop&letterbox and adjust the framerate to 25.000 (PAL). I use a high quality codec with low compression for that and don't include the audio.
4. I open the in (2) saved WAV in BeSweet and convert to 44.1kHz, 160kbit and enable the NTSC2PAL (23.976 to 25.000) "Overall Track Adjustment" to have a compliant MP2.
5. I encode with CCE.
6. I use PullDown to set the FPS of the resulting MPV to 25.000 but don't set the flags for any 2:3 pulldown.
7. I mux the MP2 and the MPV with bbMPEG.
8. I author with VCDImager.
9. I burn with CDRwin
   
10. I repeat steps (2) to (9) for the second half of the DivX as I have to split it onto 2 SVCDs.

Is this correct or am I missing s.th.?

Next is my problem with VirtualDub.
I do as I described in step (3). All runs well, just about 400 frames before it reaches the end, I get this error:

"Video compression error: The source image format is not acceptable. (error code -2)"

What does this mean? Very frustrating after waiting 2,5 hours... :(
I mean, there has been no bad frame detected on an earlier test. Every frame should have the same format, and thus the error should be thrown either at the start or never, right?

Any idea anyone?
Thanks very much.
lichtgestalt

[banjazzer]

That's not the way I would do it, particularly if I was used to encoding in PAL.

I would go with you on steps 1 and 2. (are we talking 23.970fps or 23.976fps?) And I would make sure the audio was resampled to 441,00Hz, high quality, when saving the wav.

Now I would do something different, particularly because you seem to be encoding twice, which is not necessary:

Alter the framerate in Virtualdub to 25, direct stream copy, no audio, and save the avi, which will have shrunk timewise. You now have PAL video, and audio that matches the NTSC(film) avi.

Load the wav into SoundForge ( or CoolEdit), and time stretch(shrink) to fit the new time of the PAL avi. (This should be 95.90% of the original time.)

You now have a PAL avi and a corresponding wav. These can be fed into TMPG using a PAL SVCD template, or used with CCE.

[lichtgestalt]

Hi Banjazzer!

I meant the correct 23.976 of course. Sorry for the typo.
Basically, if I see this correctly, the "NTSC2PAL (23.976 to 25.000) in Overall Track Adjustment" of BeSweet will do exactly what you'd do in CoolEdit: shrink the WAV. Plus with tooLame, SSRC, Boost etc. , which BeSweet frontends, I'll get a better quality than the stuff built into TMPEG.

If you wonder, why I crop&resize and then compress in VirtualDub to get the proper sized source video for CCE: I work better with CCE than with TMPEG and use to do VBR with 3 to 4 passes. It's faster if I have the correct-sized (480x576) video file that is processed 3 or 4 times than to i.e. frameserve through avisynth. Then the video would have to be resized every time.

Anyway, thanks for your comments. Seems like I'm on the right track.
I'll let you all know if all pans out as I proceed...

Any idea on the VirtualDub error?

cu
lichtgestalt

[edited damned speeling]

[pijetro]

Do you direct stream copy your video and audio when checking for bad frames? I had similar problems before, and it's frustrating, especially when I'm frameserving with Vdub (pretty slow). I sympathize with your dilema.

I'm no expert on this, and feel free to scream at me, but if the scan for errors didn't work, then I've noticed when I click the red/green (scene change) button, it does catch the bad frames. I don't know if there's a better app out there to scan for bad frames, or is CCE so sensitive that anything that's a bit out of whack gets halted. Perhaps it's a weaker feature of Vdub?

On the down side, you have to keep hitting that button over and over again. Not worth my time.

Good luck!!!!!!!

[banjazzer]

Basically, if I see this correctly, the "NTSC2PAL (23.976 to 25.000) in Overall Track Adjustment" of BeSweet will do exactly what you'd do in CoolEdit: shrink the WAV. Plus with tooLame, SSRC, Boost etc. , which BeSweet frontends, I'll get a better quality than the stuff built into TMPEG.

The only way TMPG comes into the audio is to convert to mp2. I don't think there is a problem with Virtualdub resampling. However, whatever tools suit will be fine.

If you wonder, why I crop&resize and then compress in VirtualDub to get the proper sized source video for CCE: I work better with CCE than with TMPEG

I understand that, but, you are still encoding one more time than is necessary, and this is not good if quality is your aim. I can't offer any advice with CCE, and I appreciate your reservations about TMPG, but can you not encode from a wav and avi with CCE? 2 encodes is one too many!

[LeeBear]

I don't know if people are expecting a big pop up message or something when VirtualDub finds an error when it scans but it doesn't. It'll go through the scan and nothing will pop up even if errors are found. You have to look at the status bar at the bottom of the window after the scan is complete to see if it found anything. It'll say something like "3 bad frames detected" etc etc.

-LeeBear

[lichtgestalt]

pietro:
Do you direct stream copy your video and audio when checking for bad frames?

Heh. Good question... I think I did, as that would be the default after opening a file... Anyway, it won't have any influence when encoding the video-only.

I don't know if there's a better app out there to scan for bad frames, or is CCE so sensitive that anything that's a bit out of whack gets halted.

I dunno either. I cannot tell about CCE being over sensitive. I haven't got to that point yet because VD keeps hanging with the mentioned error message.


Banjazzer:
I understand that, but, you are still encoding one more time than is necessary, and this is not good if quality is your aim. I can't offer any advice with CCE, and I appreciate your reservations about TMPG, but can you not encode from a wav and avi with CCE? 2 encodes is one too many!

CCE only encodes (video for my part, audio also makes problems, so I do that externally and mux afterwards), it doesn't crop, resize and letterbox. Unfortunately, or I could skip the whole VirtualDub episode... Anyway, quality shouldn't be an issue as I use the LeadTools MJPEG Codec in a high quality setting, resulting in a 4GB video-only file from a ~350MB AVI. I'd do a lossless compression if I had the HD space.
Another possibility that would circumvent the additional encoding is to use avisynth to resize etc. and feed the output to CCE. But firstly this takes much more time as it has to be done for every encoding pass. Secondly, it doesn't work with CCE 2.62 which has some nice features over CCE 2.50 and utilizes my second CPU a little bit better.

LeeBear:
I noticed that

Thanks for all your comments!

cu
lichtgestalt[/code][/b][/i]

[lichtgestalt]

Just to close the issue....
I found a "solution" by producing 3 smaller AVI files with VirtualDub instead of 1 big AVI (which has been nonetheless segmented into 2GB files....). Later in CCE I appended those three again to get one big MPV.
Hooray, you might think... Not so!
No matter how I try to mux the audio, I always get PTS/DTS underflows in bbMPEG. I tried also to shrink the WAV with Soundforge as suggetsed, but still the same errors...

I'm ready to give up! Converting DVDs was so damn easy and straight forward.

Sigh.
lichtgestalt

[banjazzer]

Couldn't you use a variant of the method used in the latest SVCD guide here? http://www.vcdhelp.com/forum/viewtopic.php?t=113698

I've only glanced at it, but using TMPG to create a project file from the DivX should deal with the cropping and resizing. This would then be converted to a pseudo-avi which can be read into CCE. Maybe I'm talking nonsense, but it's worth a look. 8)

[lichtgestalt]

Thanks for your concern, Banjazzer
Right now I'm giving a last try following 100% this guide: http://www.vcdhelp.com/forum/userguides/111846.php
Somehow I never liked DVD2SVCD and other all-in-one packages. Looked always a bit cryptic and inflexible to me... But if it solves my audio/video muxing problem I think I'll llearn to love it; at least when dealing with 23.976-DivX

I'll post my findings, though that will take some more hours. Damn, I remember when my dual PIII@550 was quite fast. Now I sure wish for some more GHz...

cu
lichtgestalt

Hopefully I haven't screwed up the cropping in avsynth...

[banjazzer]

I'd be interested to know how it works out. I haven't used CCE before, so I'm using one of my own DivX to see if I can encode to SVCD using it, going via TMPG. I will see if what I suggested actually works.

[banjazzer]

I have now run on a test on a DivX and it worked perfectly, with no sync problems. You could modify the method to suit your NTSC(film) source.

1. Open the DivX in VirtualDub. Audio> full processing mode.
Save the audio track as WAV, resampling to 44.1kHz (high quality).

2. Audio>no audio. Change framerate to 25fps. Video>direct stream copy. Save out the avi.

3. Load wav into SoundForge, and shrink to fit the 25fps avi.

4. Start TMPG. Load SVCD PAL template. Select avi and wav. (I'm not sure whether any of the filters, such as *clip frame* would work here, because my DivX did not need cropping). Save TMPG project file (.tpr)

5. Start up VFAPI converter and convert .tpr to a pseudo avi. Include the audio when you do this. (steps 4 and 5 take only a minute or so)

6. Proceed with CCE as normal, loading the avi you just created processing MPEG-2 (Elementary Stream), and tick to include the audio.

7. Multiplex .mpa and .mpv using TMPG's mpeg tools.

[banjazzer]

Just to qualify the above method...

CCE does pick up any filters chosen in TMPG, so you could crop if necessary (using the *clip frame* filter), which does not affect the aspect ratio, incidentally. And you would need to set Video source=progressive, Source aspect ratio=1:1(VGA), and Video arrange method=Full screen(keep aspect ratio).

[lichtgestalt]

You're the man, Banjazzer!

Your method does work, at least as far as my preliminary tests with a small 2 minutes clip is concerned. I only skipped the muxing in TMPGEnc as some MP2 functionality has timed out or s.th... I use bbMPEG which seems to work.
Only thing you forgot is to use PullDown to force the generated MPV to 25fps before muxing (this may be a CCE shortcoming in forgetting to set the right flags).

Now, here is the last suspicious thing: Setting the 25fps with no 2:3 pulldown results in massive PTS/DTS underflows in bbMPEG. But the movie plays OK in a player and VCDEasy doesn't complain when loading it for the authoring (haven't tried to burn and test an image for the stand-alone player).
Doing the 2:3 pulldown in PullDown results in no underflows while muxing, but slows the video down. Which is only natural because AFAIK 2:3 pulldown is used to get the fps from 30 to 24, right?

Anyway, I think going the TMPGEnc project/VFAPI route is the ticket!
Thanks Banjazzer!!

BTW, I got it also working with the mentioned DivX to SVCD Guide, but somehow the video quality was really terrible. Don't ask me why... Maybe I can find out what magick it applies to prevent underflows while muxing.

I'll keep an eye on this thread if anyone has to offer further sucggestions and will post if our now established method really did work for a complete project. This may take a while though, as I'm a bit short on time right now plus the sun is peeking through the clouds for the first time in over a week and so I can't be stuck behind a CRT, right?

Thanks again
lichtgestalt

[banjazzer]

I'm not sure where the 3:2 pulldown comes in. This only applies to an interlaced NTSC(film)source. If the source is DivX then it is progressive, and if converted to PAL it does not apply anyway! However, I'm glad you have something that works. 8)

I think you could also use Virtualdub in a similar way to the way you used it before, but instead of encoding, frameserve, and convert the vdr file to a pseudo avi with VFAPFconverter.

[lichtgestalt]

Dunno if anyone's still reading this, but...

I'd just like to announce that I have succeeded at last!
Basically it did all work as I laid out at the beginning of this thread. Though I now skip the resizing and re-encoding in Virtualdub and instead go the TMPGEnc project file plus VFAPI road Banjazzer pointed out (thanks mate!). The problem I had from the beginning (once I was able to render correctly in CCE) was when it came to multiplexing the audio and video. I kept getting massive PTS/DTS underflows in bbMPEG. We're talking several thousand ms, that resulted in unheard-of a/v sync problems in the finished MPG...
Anyway, I analysed the bbMPEG .ini files that where created by the DVD2SVCD frontend as I noticed that these errors didn't occur with it.
I found out that they use a "Forced mux rate (in 50 bytes/sec units)" of 0 instead of the for SVCD regular value of 6972!
After I adopted this change the underflows went away! I don't know if I now really got a standard compliant SVCD, but honestly, after all the trouble I had to go through I don't really care. It plays on my stand alone DVD player and that's what counts...

So, thanks everyone for your input. Much appreciated!
Take care

lichtgestalt

[banjazzer]

Of course we are still reading. 8)

[lichtgestalt]

Good to know the lookout is manned 24/7. Eternal vigilance etc...

cu on some other thread as here everything is said and done I guess.
lichtgestalt