BBMPEG: video PTS underflow at pack ...... by ......ms

[keith]

I decoded a movie with virtual dub as frameserver and CCE in VBR 1
settings 20- 300- 2400.
The audio was encoded by Tmpeg + toolame.
Muxing it with BBmpeg gives me this comment, however I did exactly as VCDhelp says.
The result is that in the beginning (first 10 minutes) the movie often stops and the sound goes faster and slower al the time.
The movie was in 25framerate and kept this way. I resised it to 480/576 for Pal. Nero acceps it without any comment.
What am I doing wrong ? The avi plays exellent.

[N0SoopForU]

Your mux rate is probably set too low, which is why you are getting underflow errors. Try setting the mux rate to 0. bbMPEG will then try to automatically detect the proper mux rate.

[keith]

I tried this but the result is the same.

[N0SoopForU]

What type of rip are you doing? VCD, SVCD, XVCD, XSVCD?

Try using the following formula to compute the mux rate:

mux rate = (video bitrate + audio bitrate) * 2.5


See if that works.

[keith]

Whitch video bitrate do you mean?
The max = 2400 but I saw in bitrate viewer that there were peaks of 2950 in my mpg file.

[N0SoopForU]

The maximum video bitrate. Since your mpeg file peaks at 2950, you should use that value instead. Here's an example assuming your audio is set to 224 kbits/s:

mux_rate = (2950 + 224) * 2.5 = 7935

In this case, 7935 should be a high enough mux rate to prevent PTS/DTS underflows.


Btw, I don't profess that this is the best way to calculate your mux rate, but it works for me. I found the formula on this forum a while back. If anyone finds something wrong with the way I am calculating the mux rate, please let me know.

[homerpez]

This worked for me...

For VCD, MPEG-1... type in 99999999 and then bbMPEG will spit back an error with a MAX number. Use that MAX number as your mux rate.

For SVCD, MPEG-2... type in 0 and let bbMPEG calculate it on its own (usually by MAX bitrate).

This is the only solution that worked for me, regarding mux rate.

I would also like to offer the same disclaimer about this as the person just above.