On Thu, Apr 06, 2006 at 01:55:19PM -0700, Steven M. Schultz wrote: > > On Thu, 6 Apr 2006, Nicolas wrote: > > > And unfortunately, I now get a frame data under-runs, which I did not > > have before. The problem occurs only if I use the -q option in the mpeg2enc > > I think the problem is the same - but the symptom has shifted slightly > because the input is (slightly) different. > > > I tried the following mplex commands, with no more luck: > > mplex -f 8 02.ac3 02.m2v -o 02_r.mpeg > > mplex -f 8 -V -r 10404 02.ac3 02.m2v -o 02_r.mpeg > > > ++ WARN: [mplex] Stream e0: data will arrive too late sent(SCR)=477476 > > required(DTS)=477419 > > ++ WARN: [mplex] Audio bd: buf= 11869 frame=000173 sector=00000077 > > ++ WARN: [mplex] Video e0: buf= 79782 frame=000129 sector=00000447 > > INFO: [mplex] STREAM bd completed @ frame 17656. > > INFO: [mplex] Scanned to end AU 14125 > > > INFO: [mplex] No. Pictures : 14126 > > INFO: [mplex] No. Groups : 942 > > INFO: [mplex] No. I Frames : 942 avg. size 68465 bytes > > INFO: [mplex] No. P Frames : 13184 avg. size 44546 bytes > > INFO: [mplex] No. B Frames : 0 avg. size 0 bytes > > INFO: [mplex] Average bit-rate : 9228000 bits/sec > > INFO: [mplex] Peak bit-rate : 9768800 bits/sec > > INFO: [mplex] BUFFERING min 17 Buf max 235543 > > **ERROR: [mplex] MUX STATUS: Frame data under-runs detected! > > > Any clue? > > Yep ;) > > It seems that the stream is slightly high in bitrate. This is a good > example of why leaving some "headroom" (not pusing things up to the > maximum limits) is a good idea. > > Look at the peak rate of 9768800 > > 9768800 + 224000 (audio) = 9992800 > > Now I use 2.5% as the overhead in a "VOB" stream so > > 9992800*1.025 = 10242620 > > and that is over the 10.08 megabits/sec for the DVD format "-f 8". > Mplex is detecting that the VBV buffer size is not sufficient to > accomodate the input streams. > > IF that analysis is correct (and I'm not way off-base which has > been known to happen ;)) then all that's needed is to get the > average bitrate down another ~160 kbits/sec. > > Couple things to try - could change the bitrate to '-b 9400'. OR > try adding "-E -10" to the mpeg2enc - that enables the 'single > coefficient elimination' rules at a moderate threshold, I have seen > that lower the average bitrate 10% without (visibly) degrading the > image. > > Good Luck! > > Cheers, > Steven Schultz
OK! Thanks for the help. I'm not re-running my Cinelerra rendering batch. The problem did not occur on all videos, but only on some of them where there was a lot of details and motion. Your advice to lower the video bitrate is probably the solution. On the other hand, I know modern standalone DVD players can play DVD whose bitrate is far larger than the official recommandation. I did not try myself, but I'll encode at 15mbps just to check it can be read. BTW, there's an interesting feature on my standalone player. It can display the bitrate using a bargraph. Is there any program on Linux which could do the same? (my home is a Windows-free environnement). Thank you, Steven! Nicolas. -- -------- Conti ---------------- O -- Kawasaki-Nikon-Linux --- ._ /\_> ------- Powered ----------- (x)> (x) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
