On Sat, Jan 04, 2003 at 22:14 -0600, christopher j bottaro wrote:
...
> here is roughtly how i'm doing it, any help would be >greatly< appreciated.
> note how i'm using the vbitrate recommended from the previous passes to
> determine the vbitrates of the current passes? am i doing that correctly?
>
> first pass:
> mencoder -dvd 1 -chapter 1-1 -ovc frameno -oac mp3lame -lameopts vbr=3 -o
> frameno.avi
> output:
> <snip>
> Recommended video bitrate for 700MB CD: 28325
this is relevant if you plan to use 700mb for whatever you're
encoding... so if you're only testing encoding for a segment, I'd use a
bitrate between for example 700 and 1000 kbps.
> second pass:
> mencoder -dvd 1 -chapter 1-1 -aspect 16:9 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vpass=1:vbitrate=28325 -oac copy -vop eq -o matrix_test.avi
> output:
> <snip>
> Video stream: 250.140 kbit/s (31267 bps) size: 6450694 bytes 206.307 secs
> 4946 frames
> <snip>
> am i suppose to use the 250.140 kbit/s in the vbitrate option in the next
> pass?
>
> third pass:
> mencoder -dvd 1 -chapter 1-1 -aspect 16:9 -ovc lavc -lavcopts
> vcodec=mpeg4:vhq:vpass=1:vbitrate=250140 -oac copy -vop eq -o matrix_test.avi
>
> done. and the resulting quality is terrible...why? thanks for the help,
> christopher
250 kbps is way too low. from the manpage:
vbitrate=<value> specify bitrate (pass 1/2) in
kBit <4-16000> or
Bit <16001-24000000>
(warning: 1kBit = 1000 Bits)
(default: 800)
I don't think -vop eq is useful for mencoder, only mplayer.
> P.S. i get this error when i do the 2nd and 3rd pass: Sorry, selected
> video_out device is incompatible with this codec.
> VDecoder init failed :(. could that have anything to do with it?
I see this too... not sure what it means but I've never worried about
it. :)