[Ffmpeg-devel] [svcd @ 0x82a1120]buffer underflow

herve.flores herve.flores
Wed Oct 4 12:26:06 CEST 2006

Le 4 oct. 06 ? 11:04, Nico Sabbi a ?crit :

> Borat wrote:
>> Nico Sabbi wrote:
>>> the easiest way to fix this issue is to raise the muxrate,  
>>> although it
>>> may render the
>>> output not strictly compliant with the target you specified
>> could you please give an example command line? This "buffer  
>> underflow"
>> warning often appeared to me, too. How does it affect the resulting
>> video?
> add something like -muxrate 3500000 (3.5 Mb/s) and up until your
> underflows are gone

sorry but it's not a real solution
I managed to reach some 50Mb/s with some sources (and with target dvd)
You can force the bitrate (or muxrate) if you want, but you'll loose  
all compliance (dvd players can usualy read 15Mb, they're more  
tolerants than the standard, but with more than 15 you're sure to  
have a freeze or to have video and audio out-of-sync)

there is a nice source to have a buffer underflow (10Mo):
or just an extract (600Ko) (the part with too much informations for  
the specified bitrate):
ex: ffmpeg -v 1 -i garfield2kitties-tlrd_h480_extract.mov -target pal- 
dvd -y toto.m2v

there is plenty of sources like that (some with too much precision  
inside, some with too much artefacts inside, etc)
too much informations in the input for a bitrate => buffer underflow
the only way to suppress them is to denoise the input (loose of  
information = no buffer underflow) :-(
ex: ffmpeg -v 1 -i garfield2kitties-tlrd_h480_extract.mov -target pal- 
dvd -nr 1000 -y toto.m2v
of course, there is no more buffer underflow with this command line  
(but always loose of quality :-(((



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