How to avoid buffer underflow

[Bozo]

I encoded a dvd-rip to svcd with the bitrate 2299(1000-2530)kbps
and audio 384 kbps

When I multiplex I get buffer underflow, It drives me crazy.

Can someone please tell me how to avoid this when encoding with cce.

I do the audio with headac3he and toolame and multplex with BBmpeg.

I'm thankful for all replies.

[Boulder]

Put 0 in the mux rate window and bbMPEG calculates the correct value.

[Bozo]

I've tried that but it didn't play correct in my dvd-player, it strange really it is a standard svcd min bitrate-1000 max-2530 avg-2299.

[Boulder]

The total bitrate is too high in the highest point. If the audio bitrate is 384kbps and the highest video bitrate is 2530kbps, the maximum will be 2914kbps. The specifications say that the maximum _total_ bitrate for SVCD is 2748kbps! This could be the problem here.

You'll find a post regarding the max bitrate here:

http://forum.doom9.org/showthread.php?s=&threadid=18257

Edit: edited the numbers a bit...

[Bozo]

I see your point but my player played a xsvcd sample with 3500kbit/s
perfectly, i found it at vcdhelp.com.

I wonder if I seat the max bitrate to say 3500 and average 2000 min 500, assuming my player only supports the standard does that mean that the movie plays fine as long as the bitrate stays under 2600kbit/s? I mean a low action movie should only stutter when the bitrate rises above 2600 and that would be just a couple of times in the movie, most of the movie should play fine.

Another question: a DVD has a average bitrate of 5000kbit/s right.

How come we do svcd with 2000kbit/s and it plays fine, it must be the lowered resolution that solves it?

[Bozo]

OH! I encoded the movie in cce with aspect ratio set to 4:3. The source was 16:9. Could that be the problem?

[adam]

The aspect ratio has nothing to do with buffer underflows.

As others have stated your total combined bitrate is too high. If you want the perfect solution to avoiding buffer underflows then simply abide by the svcd standard. It does not matter how high a bitrate your dvd player can handle, buffer underflows are caused by being multiplexed incorrectly. If setting forced mux rate to 0 auto) causes playback problems then I don't think there is anything else you can do other than lower your total bitrate. Just lower the audio, you don't need 384kbits.

What exactly do you mean when you say it doesnt play correctly? Perhaps the playback problem is related to something else?

Cds cannot be read as fast as dvds. The bitrate limits for the vcd and svcd standards are determined by how fast the data can be read off the disk. For vcds the theoretical limit is 1x and for svcd its 2x. The lower resolution is the byproduct of having a lower bitrate, not the cause. At a max of 2.6mbits, 720x480 video just doesnt look good enough so the resolution is lowered so that you get more bits per pixel.