Re: [Mjpeg-users] Strange mplex problem

[Steven M. S. <sm...@2B...>]

On Tue, 6 Jan 2004, Hans van der Made wrote:

> This used to work, but after updating it's a no-go:
> 
> mpeg2enc        --format 2                              \
>                 --aspect 2                              \
>                 --video-bitrate 1800                    \
>                 --nonvideo-bitrate 224                  \
>                 --video-norm p                          \
>                 --motion-search-radius 24               \
>                 --reduction-4x4 2                       \
>                 --reduction-2x2 1                       \
>                 --sequence-length 690                   \
>                 -o [videooutput]
> 
> Works fine:

	Everything looks good there - I see  you specified the bitrate
	as 1800 (user rate VCD) at this stage but omitted it from the mplex
	run below

> INFO: [mpeg2enc] Encoding MPEG-1 video to out.m1v
> But:
> 
> mplex -f 2 -o [output]
> 
> with previous output files doesn't!
> 
> ++ WARN: [mplex] Stream e0: data will arrive too late sent(SCR)=1942357 required(DTS)=1941882
> ++ WARN: [mplex] Video e0: buf=  25869 frame=000529 sector=00002060
> ++ WARN: [mplex] Audio c0: buf=   1818 frame=000810 sector=00000260
> ++ WARN: [mplex] Padding : sector=00000012
> ++ WARN: [mplex] Stream e0: data will arrive too late sent(SCR)=2374540 required(DTS)=2373882
> ++ WARN: [mplex] Video e0: buf=  27103 frame=000649 sector=00002527
> ++ WARN: [mplex] Audio c0: buf=   1940 frame=000993 sector=00000319
> ++ WARN: [mplex] Padding : sector=00000012
> ++ WARN: [mplex] Stream e0: data will arrive too late sent(SCR)=2622675 required(DTS)=2622282
> ++ WARN: [mplex] Video e0: buf=  36533 frame=000717 sector=00002795
> ++ WARN: [mplex] Audio c0: buf=   1986 frame=001099 sector=00000353
> ++ WARN: [mplex] Padding : sector=00000012
> [...]
> **ERROR: [mplex] Too many frame drops -exiting
> 
> Any ideas?

	Yes ;)

	For  user specified VCD (-f 2 or 5) it is necessary to specify the
	bitrate (as was done for mpeg2enc).   Add the video and audio rates,
	and then a ~2% overhead factor.

	With 224 audio and 1800 video I'd try something like

	  mplex -f 2 -r 2100 -o 'output%d.mpg' input.m1v input.mp2

	it might also be necessary to specify the video buffer size.  For
	normal VCD that is 46 but for higher rates raising that might be 
	needed.

	mplex -f 2 -b 46 -r 2100 -o 'output%d.mpg' input.m1v input.mp2

	if that has problems then increase the -b and -r values slightly

	Cheers,
	Steven Schultz