Jerky playback with vcd

[beth1949]

I guess it would help if I had been a little clearer. Before when I did 1125 bitrate with tmpgenc and then did vcd easy and nero, I still got the jerky playback. In fact when I was just doing tmpgenc and nero, it was the same kind of playback. This time the only thing that was different was bbmpeg and I still got the jerky playback but also got several places where the picture broke up. If I go lower in bitrate, won't my picture break up even more? With your samples that I downloaded the lower bitrates got rid of the jerky playback, but made the picture worse. 1125 was the lowest we could go and still get a decent picture. Why would your 1125 sample that I burned play so well and the mpeg that I burned play so bady? I still wonder about the tmpgenc settings. Maybe I need a different encoding program? Anyway, I will try again with 1100 bitrate if you think we should try it. It just doesn't make sense to me that this would work.

[vcd4ever]

Why would your 1125 sample that I burned play so well and the mpeg that I burned play so bady?

The reason could be the bitrate because a mpeg encoder can't keep the bitrate exactly 1125 and therefore the bitrate is sometimes higher than 1125 and sometimes lower that 1125. This is done by every mpeg encoder and should not be a problem for any player, but what happens if the bitrate sometimes is to high for a player.

The highest bitrate in my 1125 sample is about 1210 and because this works in your player we know that your player can handle at least 1200. What the highest bitrate is going to be depends on the source used when encoding the mpeg.

I will try again with 1100 bitrate if you think we should try it. It just doesn't make sense to me that this would work.

I think that you should try again with 1100 and also with 900. If the 1100 and 900 doesn't work then the problem must somehow be caused by the encoding or the muxing stuff. If 1100 or 900 works then the highest bitrate in your mpeg was propably to high for your player.

vcd4ever.

[beth1949]

Well, I ran through the process several time with different bitrates and using 900 got rid of the jerky playback. Not sure I fully understand why, but it did the trick. The picture is a little fuzzy, but I will take that over the jerkiness any day. I don't suppose you know of a way to sharpen the picture like it is at higher bitrate? Or am I asking too much? Also I was wondering if this bitrate will probably work with other sources, or will I have to experiment every time I want to make a vcd? Anyway, I want to thank you, thank you, thank you for spending all this time with my problems. You are a kind soul who took pity on me and I really appreciate it!

[mats.hogberg]

Well, I admire your staying power, but if I was you, and bought something that says it will play VCD (VCD bit rate is 1150, nothing else!) and it doesn't, I'd go back to the shop and get a refund.

/Mats

[Panash]

Hi vcd4ever,

I've been through the BBMepeg muxing route, and it does't help, there's something more fundementally wrong in TMPGenc.

Two options

1) ditch TMPGenc
2) ditch the DVD player

I chose 1) but its your call beth1949.

But you would have thought that by now the author of the world's most popular MPEG encoder would have wised up by now to the fact that his stuff is writing non complient MPEG. I just don't understand it. He obvioulsly hasn't tried using the Philips multiplexer. Niave or arrogant, take your pick.

To summarise, forget bitrates forget everything else, its quite simple

Philips multiplexer ok - VCD complient
Philips multiplexer not 0k - VCD non-complient
ergo TMPGenc not VCD complient end of story. Beth1949's VCD player is VCD complient, TMPG isn't.

Believe me, I've tried to feed a TMPGencoded stream through everything in Chrisondom and I can't get it to be complient.

PN

[vcd4ever]

Hi vcd4ever,

I've been through the BBMepeg muxing route, and it does't help, there's something more fundementally wrong in TMPGenc.

This is strange because i have remuxed many tmpgenc encoded mpeg's with bbmpeg and every mpeg has worked perfectly in my philips CD-i player model 450, and this player is very picky about the compliance.

I have found many problems with tmpgenc and this is a list of all the problems i have found sofar with tmpgenc's socalled vcd compliant mpeg's.

bad multiplexing, bad audiostream, bad audiopadding, sequence header problem, gop problem, setting the wrong flag in a stream header, sometimes missing a stream header,doing something that sometimes causes problems when using entrypoints and that 2 mpeg's encoded with the same settings sometimes are not exactly identical and because of this one of the mpeg's can be more compliant compared to the other mpeg.

But you would have thought that by now the author of the world's most popular MPEG encoder would have wised up by now to the fact that his stuff is writing non complient MPEG. I just don't understand it. He obvioulsly hasn't tried using the Philips multiplexer. Niave or arrogant, take your pick.

This problem exists in every tmpgenc version and because it haven't been fixed yet i don't think that the author of tmpgenc is ever going to fix it. I don't know why the author is ignoring this serious problem and perhaps the reason is that the author is naive or arrogant.

vcd4ever.

[Panash]

Pretty damming!

What is a sequence header?

The symptoms I observe with TMPGenc is that some of the frames in the GOP are played out of sequence, giving severe jerkyness. This can be caused by one of two things

1) The frames are out of sequence but are numbered correctly
or
2) The frames are in sequence but are numbered incorectly

Is this a sequence header problem?

Clearly both beth1949 & my VCD players choose the opposite implimentaion to the rest which is the where TMPGenc has its error. Whilst it would be totally MPEG correct, it gives jerky playback from TMPGenc - which is incorrect (there simply is no getting round the fact that TMPGenc writes faulty MPEG).

Seems that the Philips 450 is picky in a different way. Perhaps I'll try again if I get time.

PN