[MPlayer-users] maybe a bug in mpeg1video output (a/v async inlatter processing)?

[Ivan Kalvachev]

This is problem that is quite known.
First mencoder is done with avi in mind, and this made him totaly
avi orientated. One of the bad things it does is to write an zero byte
lenght packet that mean the last frame should remain visible as it is.
Of cource this is not allowed in mpeg. But it is still done!

As workaround dalias have created an vf_softdup filter that repeats
the frame instead writing these hacks.

Another more drastic workaround is to disable frame skip/dublicate
code with -mc 0, try and see what works better for you.

Also make sure that you use the latest CVS version, as there
have been done some modifications to mpeg muxer that
(I hope) fix system timestamps and presentation/display timestaps.
(with better knowlgade of bitrate etc.)

Best Regards
   Ivan Kalvachev
  iive



Thorsten W. Schmidt said:
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> Hash: SHA1
>
> hello
>
> i use the following system:
> - - suse 8.2 with kde 3.2.2
> - - hauppauge wintv with bt878
> - - kernel 2.4.20
> - - libc 2.3.2
> - - gcc 3.3
> - - ld 2.13.90.0.18
> - - GNU assembler 2.13.90.0.18
>
> cpu (amd xp 2600+ with fsb down clocked to 111MHz:
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 6
> model           : 6
> model name      : AMD Athlon(tm) Processor
> stepping        : 2
> cpu MHz         : 1393.989
> cache size      : 256 KB
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : no
> coma_bug        : no
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
> cmov pat pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow
> bogomips        : 2778.72
>
> capture card (lspci):
> 00:0b.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture
> (rev 02)
> 00:0b.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev
> 02)
>
> and software:
> - - mplayer 1.0pre4-3.3
> - - mjpegtools-1.6.2-1 (used tool: mplex)
> - - mpgtx-1.3-2 (used tool: mpgdemux)
> - - dvdauthor-0.6.9
>
> - -----------------------------------------
> to record video from my hauppauge i use the following command line. the cpu is
> at about 55%. i also recorded with low resolution (cpu at 20%), but the
> result is the same. also tried to do it as root with "nice -n -20" with the
> same result. here the commandline:
> "mencoder -srate 48000 tv://R6 -tv
> driver=v4l:alsa:volume=65535:width=720:height=576:audiorate=48000 -vf pp=fd
> - -ovc lavc -lavcopts
> vcodec=mpeg1video:vbitrate=1000:keyint=25:abitrate=224:acodec=mp2:aspect=4/3
> - -oac lavc -of mpeg -o /backup/test.mpg"
>
> while recording i frequently (about 150 per hour) get:
> "Unknown block type, possibly non-MPEG stream!"
> it looks like each line stands for a single droped frame. also mplayer reports
> while recording
> "Pos:3600,0s 89877f (0%) 25fps Trem:   0min   0mb  A-V:0,000 [999:224]". so it
> seems mplayer droped 123 frames in one hour. is it possible to duplicate the
> last frame if the current one was droped?
>
> the output is a working mpeg stream. everything seems to be fine. but
> dvdauthor doesn't recognize it as a valid mpge1 stream. dvdauthor reports:
>
> "STAT: Processing test.mpg...
> WARN: Skipping sector, waiting for first VOBU...
> WARN: Skipping sector, waiting for first VOBU...
> ...
> WARN: Skipping sector, waiting for first VOBU...
> WARN: Skipping sector, waiting for first VOBU...
> WARN: Skipping sector, waiting for first VOBU...
> ERR:  SCR moves backwards, remultiplex input."
> - -----------------------------------------
> so i tried to demux and remux the output of mplayer with:
> "mpgdemux -X -P -N -b chunk -f test.mpg"
> "mplex -f 8 -o test2.mpg chunk-0.m1v chunk-0.mp2"
>
> this file is working with dvdauthor (no error), but audio and video are not
> synchron anymore. when i record a 30 minutes piece, the difference is about 3
> seconds in the end. when i record 90 minutes the difference is about 8
> seconds in the end.
>
> greetings
>   thorsten
> - --
> +-----------------------------------------------------------------------
> | Dipl.-Inform. Thorsten W. SCHMIDT
> | Lehrstuhl Angewandte Informatik III (Robotik und Eingebettete Systeme)
> | Universitaet Bayreuth, D-95440 Bayreuth, Germany
> | Tel: +49 (0)921-55-5163, Fax: +49 (0)921-55-5162
> | eMail: Thorsten.W.Schmidt at uni-bayreuth.de or t_w_s at web.de
> | Http://ai3.inf.uni-bayreuth.de or http://www.tws-home.de
> +-----------------------------------------------------------------------
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