[MPlayer-users] Recoding to VCD Using MEncoder Only

[Nico Sabbi]

Gordan Bobic wrote:

>On Monday 10 May 2004 17:03, Nico Sabbi wrote:
>
>  
>
>>>>>Is there any reason why this cannot be done? I presume that it
>>>>>cannot be done, since I have found the mencvcd script in the TOOLS
>>>>>directory which seems to use an exceedingly long winded way of
>>>>>recoding files into VCD format, using mjpegtools.
>>>>>
>>>>>I think I have managed to get the mencoder setup almost right to
>>>>>achieve the same thing without the clutter of all the other
>>>>>seemingly inferior tools and overheads of doing the same job
>>>>>several times, but I am stuck in one last tiny detail.
>>>>>
>>>>>Here is the script I use:
>>>>>
>>>>>#!/bin/bash
>>>>>mencoder	-oac lavc	\
>>>>>		-ovc lavc	\
>>>>>		-ofps 25	\
>>>>>		-of mpeg	\
>>>>>		-lavcopts
>>>>>vcodec=mpeg1video:acodec=mp2:vbitrate=1150:abitrate=224:vrc_buf_si
>>>>>ze =327:vrc_maxrate=1150
>>>>>          
>>>>>
>>>>you missed keyint=12, but generally dvd players tolerate much
>>>>longer values;
>>>>        
>>>>
>>>Ah, OK. Is 12 really what the spec for VCD says? That sounds rather
>>>small...
>>>      
>>>
>>yes it's tiny, and if I remember correctly it's the value stated in
>>the specs, but following the standard at the letter with modern
>>players is quite useless.
>>In my opinion you can safely use a larger value.
>>    
>>
>
>OK, thanks. I'll up that to around 125, and see if it works on a few DVD 
>players...
>
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>>>>2 passes and mbd=2 are reccomended
>>>>        
>>>>
>>>OK, I'll try it with mbd=2 and see if it looks better...
>>>
>>>      
>>>
>>>>>\
>>>>>		-vf scale=352:288,dsize=4/3	\
>>>>>		-af resample=44100:0:2	\
>>>>>		$1 -o $2
>>>>>
>>>>>This seems to work really well, except for one small problem - the
>>>>>"-af resample=44100:0:2" part doesn't seem to do what the
>>>>>documentation says it should (or maybe I am reading it wrong).
>>>>>          
>>>>>
>>>>-srate 44100 usually works well
>>>>        
>>>>
>>>Ah, excellent, thanks, that did the trick. :-)
>>>
>>>      
>>>
>>>>>I have videos encoded with varying frequencies other than 44100
>>>>>(e.g. 22050, 48000), and I have to make this into 44100 to make it
>>>>>VCD compliant. However, the files encoded using the above script
>>>>>still have the same audio frequency (confirmed using "mplayer
>>>>>-identify") as the source file. The video seems to be in the
>>>>>correct format, but the audio is not.
>>>>>
>>>>>What I am I doing wrong? I would really like to avoid using the
>>>>>mjpegtools script if at all possible because it takes much longer.
>>>>>          
>>>>>
>>>One last problem - the "dsize=4/3" (or "dsize=1.333333") parameter
>>>doesn't seem to set the aspect ratio in the resulting file. I know
>>>that this is being really pedantic, but I have heard that VCD MPEG
>>>video should have it. Can anybody confirm or deny this, and if it
>>>is required, how do I make it stick on the encoded file?
>>>      
>>>
>>dsize is useless, instead add to lavcopts ...:aspect=4/3:...
>>    
>>
>
>Thanks, that did the trick. It all seems to be working now, and it is 
>considerably more elegant than the mjpeg tools solution with stripping 
>out the audio and video separately, transcoding them, and only then 
>recombining them. :-)
>
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almost :) you had better install libdvb from www.metzlerbros.de and run

dvb-mplex -t XVCD -o dest.mpg orig.mpg


>All I have to do now is burn it onto a CD and see if it works on a DVD 
>player...
>
>Thanks for the help, I really appreciate it.
>
>Gordan
>
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