Antw: Re: [MPlayer-users] (no subject)

[Nico Sabbi]

nick.rienties at home.nl wrote:

>>Van: Nico Sabbi <nsabbi at tiscali.it>
>>Aan: "MPlayer usage questions, features,  bugreports" <mplayer-users at mplayerhq.hu>
>>Datum: wo 27 okt 04, 12:11
>>Onderwerp: Re: [MPlayer-users] (no subject)
>>
>>nick.rienties at home.nl wrote:
>>
>>    
>>
>>>Hi,
>>>
>>>I recently start using Mencoder to make backups of my DVD's. The command I use to encode a DVD:
>>>
>>>mencoder -dvd-device /mnt/dvd/ dvd://1 -oac copy -vf crop=xxx:xxx:xx:xx -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=9999:vhq:vpass=1 -o ~/movie.avi
>>>
>>>mencoder -dvd-device /mnt/dvd/ dvd://1 -oac copy -vf crop=xxx:xxx:xx:xx -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=9999:vhq:vpass=2 -o ~/movie.avi
>>>
>>>I encoded several movies with these setting, which gave the following result:
>>>
>>>Playing American History X.avi.
>>>AVI file format detected.
>>>AVI: ODML: Building odml index (2 superindexchunks)
>>>VIDEO:  [DIVX]  704x576  24bpp  25.000 fps  4221.6 kbps (515.3 kbyte/s)
>>>Clip info:
>>>Software: MEncoder 1.0pre5-3.3.4
>>>
>>>Playing Hero.avi.
>>>AVI file format detected.
>>>AVI: ODML: Building odml index (2 superindexchunks)
>>>VIDEO:  [DIVX]  720x432  24bpp  25.000 fps  5310.8 kbps (648.3 kbyte/s)
>>>Clip info:
>>>Software: MEncoder 1.0pre5-3.3.4
>>>
>>>Playing Kill Bill 2.avi.
>>>AVI file format detected.
>>>AVI: ODML: Building odml index (2 superindexchunks)
>>>VIDEO:  [DIVX]  720x416  24bpp  25.000 fps  2612.0 kbps (318.8 kbyte/s)
>>>Clip info:
>>>Software: MEncoder 1.0pre5-3.3.4
>>>
>>>Question is:
>>>
>>>Why is there so much difference in the used bitrate?
>>>Is the bitrate setting over kill? I do care about filesize, 4485 MB is the max since the avi should fit on a dvd5.
>>>Are there any other settings that I could use in the encoding command?
>>>
>>>Kind Regards,
>>>Nick
>>>
>>> 
>>>
>>>      
>>>
>>because lavc used all the bandwidth it needed, so it saturated.
>>If you want to fill all that space the vbitrate setting is nonsense:
>>you should use vqscale=2 and a single pass instead. And don't forget
>>to add :autoaspect, or you will have egg-heads :)
>>
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>>MPlayer-users at mplayerhq.hu
>>http://mplayerhq.hu/mailman/listinfo/mplayer-users
>>
>>    
>>
>
>If I use the vqscale option instead of vbitrate, how do I set a boundry for the filesize (4.38 GB max)?
>Also is it just a waste of dvd space using vqscale, since vbitrate already used all it needed?
>  
>

you can't but for 2 hr of movie you can use at most ~ 5000 kb/s for 
video; typically lavc
will top around 4500 if you clean the source with hqdn3d, and average 
even lower,
at least when encoding with the usual size parameters; in addition a 
single pass will take
half the time and with vqscale=2 you will get uncompromised quality.
If you want to limit the filesize then the usual two-pass procedure is 
fine, but you have
to calculate the right bitrate.

>The Man page says the following about aspect ratio:
>
>Store movie aspect internally, just like with MPEG files. Much nicer than rescaling, because quality is not decreased. Only MPlayer will play these files correctly, other players will display them with wrong aspect. The aspect parameter can be given as a ratio or a floating point number. 
>EXAMPLE: 
>aspect=16/9 or aspect=1.78 
>
>Does this mean that if autoaspect isn't used other players will play the file correctly but Mplayer won't?
>
>  
>
the opposite: Mplayer will play it correctly, others may not. I can 
confirm that rescaling
always reduced quality by a large factor in all my experiments