[MEncoder-users] filter question (converting low quality dvds to xvid = larger files)

[Kerry Kirk]

On Sun, Mar 22, 2009 at 1:08 PM, James Hastings-Trew <jimht at shaw.ca> wrote:

> Kerry Kirk wrote:
>
>> James,
>>
>> Thanks for the reply.  Yes it is an NTSC video and I also forgot to
>> mention
>> that I am running a 64bit os if that matters.
>>
>> Should filters be applied to both passes or to the second pass only?
>>
>> K.
>>
>> On Sun, Mar 22, 2009 at 2:44 AM, James Hastings-Trew <jimht at shaw.ca>
>> wrote:
>>
>>
>>
>>> Kerry Kirk wrote:
>>>
>>>
>>>
>>>> First some background:
>>>> I am on an Ubuntu 8.10 box and am using MEncoder 2:1.0~rc2-0ubuntu17
>>>> with
>>>> libxvidcore4 2:1.1.2-01ubuntu3 (according to Synaptic)
>>>>
>>>> When I convert my dvds to xvid my process is as follows.
>>>>
>>>> Using dvdshrink via wine I rip out the parts I want, decrypt them and
>>>> save
>>>> the results as an iso.
>>>>
>>>> I have a script file that will process as many iso files as I request by
>>>> mounting each iso as an iso9660 loop and issuing the following commands
>>>>
>>>> first pass
>>>> mencoder -dvd-device /pathtoisofile dvd://1 -nosound -ovc xvid
>>>> -xvidencopts
>>>> pass=1:turbo -passlogfile xvidlog -o /dev/null 2>>errorlog
>>>>
>>>> second pass
>>>> mencoder -dvd-device /pathtoisofile dvd://1 -oac mp3lame -lameopts
>>>> cbr:br=96:vol=8 -alang en -ovc xvid -xvidencopts pass=2:bitrate=900
>>>> -passlogfile xvidlog -o outputfile.avi 2>>errorlog
>>>>
>>>> I generally get a 2 hr movie down to about 650-700 megs.  With a few
>>>> dvds
>>>> of
>>>> very old movies where the quality of the original is lacking the files
>>>> end
>>>> up being much larger.  I am guessing that the static and
>>>> jitteriness(sp?)
>>>> of
>>>> some of these old films is the cause of the difference in compression
>>>> and
>>>> thus file size.
>>>>
>>>> Are there any commands or filters I should add to my encoding commands
>>>> that
>>>> might get some better quality xvids out of the older films.  I have used
>>>> grayscale in the xvidencopts and it does seem to help with the b&w
>>>> films.
>>>> Any other ideas?
>>>>
>>>>
>>>>
>>>>
>>> Couple of things come to mind - pullup, deinterlace, scaling, cropping,
>>> hqdn3d. You are encoding the movies without doing any of these things
>>> which
>>> means you are burning bitrate on more frames than you need to (unless
>>> these
>>> are PAL DVDs, you didn't say), more detail than you should be (interlace
>>> is
>>> for TV, not for computers), pixels you don't need (DVDs are encoded at TV
>>> aspect ratios, generally storing more pixels than the computer needs to
>>> display them properly), black borders, and noise.
>>>
>>> -vf pullup,softskip,pp=lb,hqdn3d,harddup will give you a push in the
>>> right
>>> direction IF the DVD source is NTSC, a movie shot on film, and I can't
>>> guess
>>> at valid values for cropping and scaling, but in gneral a full screen DVD
>>> with no cropping needs should be scaled to 640x480 to maintain proper
>>> aspect
>>> ratio.
>>>
>>>
>> both passes. :)


Thanks for all your help.  I do have one more question.  If I am going to
watch the avi on both television (via an xbox with avi coming through a
local network) AND on a computer screen should I go ahead and deinterlace?