Ulead Go-DVD Plugin with SVCD

[mentat]

I have been attempting to get an SVCD compliant MPEG to work with this plugin with little success. I have tried both Cinema Craft and Ligos as encoders but always get the same probelm.

The plugin accepts the MPEG stream and identifies it as SVCD. It is during the entry point insertion that problems appear. The file plays ok but if you start using the slider to move around in the file the video breaks up (green blocks appearing everywhere) and video and audio get out of sync. I am interested if anyone has had any success with creating SVCD's using the plugin and what settings you used in the MPEG file. The plugin works fine with VCD MPEG-1 streams I have created.

My setting for SVCD were:

MPEG-2 VBR

Max video bitrate: 2539Kbps (this is the limit enforced by Ligos for SVCD and since the Go-DVD plugin uses Ligos you would assume this is correct)

Audio bitrate: 192kbps

Sequence headers added before every GOP.

I would really like to be able to use the plugin with files produced by Cinema Craft as this encoder allows forcing of frame accurate I-frame points in the output file which are exactly what the plugin looks for when allowing you to choose entry points. Any help or experience would be appreciated!

Thanks,
Rob

[mentat]

Still no luck with Cinema Craft but success with TMPGEnc.

Used Tsunami 2-pass vbr with max video at 2539Kbps, audio at 192Kbps to SVCD and the plugin used it perfectly.

I didn't realise but Tsunami allows you to force I-Frame insertion just like Cinema Craft. On the GOP tab you can switch off auto I-Frame insertion and then provide a list of frames to make I-Frames. You can run an auto pass first to let the encoder decide what frames it thinks should be I-Frames and then you can add any extras of your own. By knowing frame numbers of chapter entry points within the original VOB from the DVD you can run the auto mode and if any of the chapter points aren't auto selected add them manually.

Then with the plugin you can make an SVCD with frame accurate chapters at the exact points they are on the DVD. Thy are not exclusive chapters like a DVD but unfortunately neither VCD or SVCD support exclusive chapters. The plugin will also create the menu pages with snapshots of each entry point just like the chapter selection pages on DVD. Very cool!!

[digvid]

I have been doing the same thing as you--manually setting chapter beginnings as I-frames in TMPGEnc. However, when I try to locate these frames in the DVD plug-in in Ulead, I find it very tedious locating them. Do you have a convenient way of doing it? Also, I found that when played on my Hollywood+ decoder, the chapters would start with a flash of green blocks for just a second or so. I used TMPGEnc SVCD-compatible with Manual VBR at 2048kbps max, 128kbps audio.

- digvid

[mentat]

I use a program called ifo_read which is supposed to be use to create projects for I-Author but it also creates an information file with exact time points for chapters. Using these I calculate the exact frame positions and enter these in TMPGEnc.

In GoDVD I just move the slider till it is within about a second or two of the chapter point and then use the arrow keys to move to the exact I-Frame. Not great but it works.

The reason you are probably getting the green blockiness at the start is to do with closed and open GOPs. I have yet to completely finish and create an SVCD to test in my standalone DVD player but I assume I will see the same. Even though you are forcing a particular frame to an I-Frame the B and P frames that follow are allowed in MPEG to reference the previous GOP. Since you haven't read the previous GOP due to jumping in at the entry point the green blockiness appears. The advantage Cinema Craft has over TMPGEnc is that when you set a forced I-Frame in CC it also creates a closed GOP which means none of the frames reference frames outside of that GOP. This is absolutely what you should do for true chaptering points. Unfortunately TMPGEnc doesn't seem to do this and thus the green blockiness. The other sad news is that I cannot get the plugin to correctly handle a SVCD stream created with Cinema Craft. In setting the entry points the picture breaks up and sound gets out of sync.

Hope that helps,
Rob

[mentat]

A closer look at TMPGEnc and I noticed it does allow you to set closed GOPs. The unfortunate problem (I still have to confirm) is that it will set all forced I-Frames to closed GOPs which is a bit of a pain. Its not the end of the world but with closed GOPs and maintaining a set bitrate you will more than likely obtain slightly less picture quality than using open GOPs. Therefore it is best to limit the use of closed GOPs to only the absolutely necessary points - being chaptering points. Now the argument is that if TMPGEnc scene detection code is accurate the I-Frames it chooses would be unlikely to be referencing previous GOPs as the pictures would looking nothing alike and therefore making them closed GOPs is likely to make no difference.

I run the auto detection feature first with force I-Frame settings so it identifies scene changes. Then if it has missed any chaptering point using the auto detect I add those manually.

I will have to run some testing to confirm the theory!!

Bye,
Rob

[digvid]

The problem I have with using timecodes in the DVD plug-in to find the I-frames is that if you encode your SVCD as a VBR file, the timecodes displayed in the DVD plug-in do not match the timecodes of the DVD.

- digvid

[mentat]

I am assuming by the fact the the timecodes in your SVCD don't match the timecodes on the DVD is a result of you converting an NTSC DVD and having to do 3:2 pulldown or something. I am lucky and living in Australia we use PAL. The timecodes on my SVCD perfectly match the timecodes on the DVD. I have also found using SmartRipper it outputs an info text file with frame numbers of chapter points. I simply put these in as I-Frames in TMPGEnc and then calculate into timecodes to find in plugin.

The timecode display in the plugin is hours, minutes, seconds, frames. So 00:02:12:21 relates to 2 minutes, 12 seconds and 21 frames. Therefore for PAL the last figure ranges from 0 - 24 (PAL having 25 fames per second).

Hope that helps,
Rob

[digvid]

Rob -

I have converted my clip from 29.97fps to 23.976 w/3:2 pulldown at playback. However, this is not the cause of the mismatched timecodes. I find that regardless of the fps of the clip, the timecodes are wrong if I use VBR encoding. If I encode to mpeg1 or CBR mpeg2, the timecodes match perfectly.

- digvid

[Hans Herbert]

Ulead DVD Plugin , does always accept INTERLACED Source !!!
( Field A ) , when you Encode " Non - Interlaced " (Progressive) , the Plugin say , Not a SVCD File !

[digvid]

The plug-in does seem to accept my progressive clip, and the summary screen says that it is recognized as SVCD. It is only when it searches for chapter points that it has a problem.

I guess I should try using an interlaced clip with the plug-in just to see if it works. If it won't work with progressive though, the plug-in will be useless to me, since most of my clips are 23.976 w/3:2 pulldown. If the plug-in won't accept them, I think that is pretty shabby, because I have a copy of the Philips spec for SVCD, and it says that mpeg files at 23.976 fps with 3:2 pulldown are accepted by the standard.

- digvid

[mentat]

Have you got the latest patch to the plugin. The initial version was completely useless in my opinion - couldn't get it to work properly with anything. Always crashed and the selecting of the chaptering points was buggy as all crap. They recently (in the last few weeks) released a patch that at least addresses some of these problems.