[MPlayer-users] Encoding, reencoding and alsa

[EC]

On Fri, Aug 19, 2005 at 06:56:57PM -0400, Bradley Alexander wrote:
> I'm having issues with encoding video, apparently since the change to the DivX 
> codec within mplayer.
Are you talking about FFmpeg switching the fourcc for their mpeg-4 codec
to "FPM4"? Although it breaks compatibility with some standalone
players, the only difference in the output is 2 occurances of "FMP4"
instead of "DX50" or whatever it was before.  Use -ffourcc DX50 or open
up the output in a hex editor to negate the effects of this.

> where #FFMPEGCODEC# is DivX5.0, #VBITRATE# is 800 and #ABITRATE# is 128.
What is this DivX5.0 codec by libavcodec you are talking about?  Just
their "mpeg4" one?  If you are trying to do it in realtime, depending on
the source and your cpu, I would use a different bitrate/ codec. Mpeg-2
with a high bitrate to make sure you dont get any artifacting maybe?

> After recording, I pull the commercials with avidemux, then re-encode to 
> usable size (~350MB/hour). The command I use to re-encode is a script using a 
> two-pass method. My command line is 
> 
> mencoder ${infile} -o ${outfile}  -oac copy -ovc lavc -lavcopts 
> vcodec=mpeg4:vbitrate=${bitrate}:vhq:vqmin=2:vlelim=-4:vcelim=9:lumi_mask=0.05:dark_mask=0.01:vpass=2 
> -vf scale=640:480 -sws 2 -vop pp=fd
-vop is obsolete. pp can be appended to the -vf filter chain.

> I have tried both -ffourcc DX50 and -srate 48000, which are steps I found 
> either on the mailing list or linked from google. 
> 
> And since the change of codec, some of my mplayer installations (Marillat's 
> mplayer-1.0-pre7-0.0 deb) give me the following error:
> 
> Cannot find codec matching selected -vo and video format 0x34504D46.
> Read DOCS/HTML/en/codecs.html!
> ...
> AO: [oss] 44100Hz 2ch s16le (2 bps)
> Building audio filter chain for 44100Hz/1ch/s16le -> 
> 44100Hz/2ch/s16le...
> Video: no video
Do you have a /etc/codecs.conf? Try getting rid of it if you do.

> 
> The machines which "work" (Marillat's mplayer-1.0-pre7cvs20050716-0.0 deb) 
> still give me 
> 
> alsa-space: xrun of at least 0.061 msecs. resetting stream?,?% 0 0 82%          
> alsa-space: xrun of at least 0.071 msecs. resetting stream1.8% 3 0 77%          
> alsa-space: xrun of at least 0.067 msecs. resetting stream1.5% 4 0 73%          
> 
> and the video is very choppy. Since I cannot access the manual, can someone 
> help me to get this working? Things that were recorded long ago (late last 
> year) perform fine, its just stuff recorded in the last several months, since 
> the changes to the codec.

are all your codecs up to date?  I am not sure what your problem is, are
you getting that error on your output video, after encoding with
vcodec=mpeg4?

//Eli