Hi, I am converting some files to mpeg2 raw video (PAL DVD) and I am getting a lot of messages like this: [mpeg2video @ 0x857b330]rc buffer underflow [mpeg2video @ 0x857b330]rc buffer underflowin 449mb A-V:0.000 [2904:0] The command I am using is: mencoder -of rawvideo -vf scale=720:576,harddup -nosound -ovc lavc -lavcopts vcodec=mpeg2video:keyint=25:vbitrate=4305043:aspect=4/3:vrc_maxrate=9800:vrc_buf_size=1835:vpass=2 -mpegopts format=dvd -speed 40000/40000 -ofps 25 -passlogfile video.pass -o video.m2v video.ogm Later when I try to mplex these, I get a lot of errors (I am unsure if the problems are related, but I suspect that the mencoder buffer underflows are responsible). I would be grateful to know what causes these buffer underflows and what (if anything) I can do to fix them. n0dalus.
n0dalus wrote:
Hi,
I am converting some files to mpeg2 raw video (PAL DVD) and I am getting a lot of messages like this: [mpeg2video @ 0x857b330]rc buffer underflow [mpeg2video @ 0x857b330]rc buffer underflowin 449mb A-V:0.000 [2904:0]
The command I am using is: mencoder -of rawvideo -vf scale=720:576,harddup -nosound -ovc lavc -lavcopts vcodec=mpeg2video:keyint=25:vbitrate=4305043:aspect=4/3:vrc_maxrate=9800:vrc_buf_size=1835:vpass=2 -mpegopts format=dvd -speed 40000/40000 -ofps 25 -passlogfile video.pass -o video.m2v video.ogm
although it's not related to your problem, -of rawvideo and -mpegopts combined together are 100% nonsense: when you mux to rawvideo you don't use the mpeg muxer. Additionally. -speed 40000/40000 doesn't have any logic
Later when I try to mplex these, I get a lot of errors (I am unsure if the problems are related, but I suspect that the mencoder buffer underflows are responsible).
I would be grateful to know what causes these buffer underflows and what (if anything) I can do to fix them.
n0dalus.
try to add a sensible vrc_minrate with lmin=1:vqmin=1:mbqmin=1
On 9/29/05, Nico Sabbi <nsabbi@tiscali.it> wrote:
although it's not related to your problem, -of rawvideo and -mpegopts combined together are 100% nonsense: when you mux to rawvideo you don't use the mpeg muxer. Additionally. -speed 40000/40000 doesn't have any logic
Oops. The reason that's there is because I wrote a script to generate the mencoder commands given what data it can parse from a quick test run of mplayer (it works out what settings to add black bars, resize, change framerate, bitrate etc.) Originally it was only for avi to dvd, and I only later added support for raw mpeg2 output, I accidentally left in some of the options.
try to add a sensible vrc_minrate with lmin=1:vqmin=1:mbqmin=1
When I use vrc_minrate as well as vrc_maxrate I get a warning: [mpeg2video @ 0x857b330]Warning min_rate > 0 but min_rate != max_rate isnt recommanded! I assumed I must have done something wrong so I took out my vrc_minrate option. Also, according to the manpage, vqmin=1 is: "Not recommended (much larger file, little quality difference and weird side effects: msmpeg4, h263 will be very low quality, ratecontrol will be confused resulting in lower quality and some decoders will not be able to decode it)." I know you have done development on mencoder's mpeg muxer, so I trust your opinion, I am just a little confused on why you recommended these options. n0dalus.
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Nico Sabbi