stuttering SVCDs, what is cause?

[lukester01]

I have been trying to diagnose why I am getting stuttering SVCDs. The stutter is every 2-3 seconds.

I have a JVC XV-S62 DVD player.
Using Imation CD-Rs, burned at X32 in a X52 burner, even tried X8 and still stutter.

Used TMPGenc to encode, CBR at 2520 kbps. Top field first. High quality.
I tried de-muliplexing to seperate video and audio, and then recombining them from seperate files, (is this step really necessary?)and that didnt help. Quality is great, but they stutter.

If I encode CG at 75%, it doesnt stutter, but the quality is CRAP.

I have tried CBR at 2300, and it still stutters, and quality is CRAP.

All the encodes work on the PC with no stutter.

The only thing I can think that the problem could be is that the player is having trouble reading it. Is it the Media? or do I need to try the 'trick' so that the player thinks it is a VCD?

[adam]

How high is your audio bitrate? The SVCD standard only supports a max total bitrate (Audio + Video + Subs + additional overhead) of 2778kbits. If you go over this then your disk is non-compliant and may skip or not play at all on any given SVCD compliant player.

Even if you are under this limit, some players do not conform to spec and as you apparantly have noticed, you may be forced to lower your bitrate. I find it hard to believe though that CBR 2520 looks "great" and CBR 2300 looks "like crap." There shouldn't be all that much difference in quality.

I know you said the problem was solved by lowering the bitrate, but this also seems like it could be a field order problem. Try double clicking on the deinterlace filter in TMPGenc and setting the filter to even field (field) and previewing the movie frame by frame. If the stuttering is present there then you have the wrong field order and need to switch it on the advanced tab...don't forget to disable the deinterlace filter afterwards.

[lukester01]

Changing the Field order didnt help. (or hurt)

here are the results of some more test runs.

Media brand did not make a difference.

CBR 2300kbps - stutter, bad pic
VBR 2 pass - stutter, good pic
CG 75 - no stutter, bad pic
CG 100 - stutter, ok pic

Seems the only way to get it to work is CG75 , but the pic is not very good, even at CG 100 the pic wasnt as good as the CBR encodes.


Is the De-multiplexing step essential to create SVCDs? I notice that when I do this that the audio gets out of sync on the encode.

[lukester01]

Oh, I should also add that all encodes work without stutter on the PC, and that I burned them all using NERO 5.5.19 and the speed of the burn didnt help.

[sammie]

What brand player are you using (presuming you are talking about stand alone and not your 'puter)? I've noticed that a lot of the ones that say they support SVCD don't really. They recognize the disk and something comes up, but you do see a lot of stutter and freezes. I've tried about 5 different stand alones with the same commercial SVCD disk only 2 played it well. 4 our of 5 played a non-compliant VCD much better, but you did have to use the header trick.

[lukester01]

Tried VCDEasy to rule out burning software, and it too has stutter.
Tried the 'trick' and it also stuttered.

The player is a JVC XV-S62 and though the section here has people that claim it works 'sometimes', I am starting to think it is incapable of the higher bitrate.

Based on my post above, that lists what did work and what didnt, what would I have to lower my bitrate too in CBR (since it seems to get the best picture)to get it to work?

I think I will try different runs with the CG setting higher than 75 to see where the break point is.

[adam]

What is CG? Do you mean CQ?

Well, like I said the total combined bitrate allowable is 2778kbits. So if you use no subs and an audio bitrate of 224 then you should be able to use CBR of 2520 with no problems, but these numbers really only exist on paper. The only way to find out high high a bitrate you can get away with on your player is to simply run some tests yourself.

As far as demultiplexing and then remultiplexing, yes with TMPGenc it is actually necessary but you can save yourself alot of time and trouble by just encoding the streams separately to begin with. This way you just multiplex in the end and skip the demux stage. TMPGenc has had a long standing bug where its program streams are improperly muxed. So you must encode to elementary streams and then multiplex again, or as you've been doing, demux and then remux.

Before you give up on your hardware player try remuxing in bbmpeg instead. I find TMPGenc to be an absolutely horrible mpeg2 muxer. I have some old SVCDs muxed with TMPGenc that won't play on various players, yet all the ones muxed with bbmpeg work fine. An improperly muxed SVCD WILL cause stuttering on some dvd players.

[sammie]

If it still stutters with the header trick then it's probably a total bitrate thing as Adam talked about. Try a series of small encodes 10 minutes of video should be enough at different bitrates and find the "threshold". Hopefully, the threshold will be someplace you can live with.

@Adam I useed to use bbmpeg to multiplex for same reason. But then about 6 months ago I used TMPEGenc again. Worked fine. Been using it exclusively since and haven't seen a single problem. Does anyone know if the problem is still there, or is it one of those ingrained things that we've all "known" about for so long.

[lukester01]

OK I am confused.

If I use bbMPEG do I still have to take the original mpg and split into seperate Video and Audio streams?

Can you give me a quick procedure. (including when and how to split the original mpeg into 35 min chunks)

This is what I have been doing.

1) simple de-multiplex to split 2hr mpg into video and audio.
2) use TMPGenc to encode those two streams into a SVCD compliant mpg, setting start and end points to get only 35min chunks. (but audio seems to get out of sync)
3) burn resulting mpg using NERO

[Wolfmancatsup]

Hi - whereabouts do you live? I live in the UK and have had similar probs with ntsc -> pal converted svcds... it seems as if the picture stops for an extra frame or two every second or so. The same as your problem or am I talking out of you-knop-where?


Wc

[lukester01]

I have another question too, the guides all show the aspect ratio being set at 1:1 (VGA). When I did my encoding, that was always set to 4:3 for both the source and video setting screen.

My source mpg was meant to be viewed in NTSC.

[lukester01]

Got it working good now. Here's what worked in TMPGenc

CQ 85 (90 would stutter)
Encode mode: Interlaced
Highest Quality (very slow)

Noise reduction
100 (really helped clear up the image)
1
20

Non-Interlaced (source)
Top First
4:3 NTSC(704x480)
Full Screen


max bitrate 2530
min bitrate 300
Padding on
B pic spoilage 20

[lukester01]

Oh, and I didnt need to de-multiplex into seperate Video & Audio streams.

I just used the original mpg as the source and then using TMPGenc just encoded 35 min at a time.