Re: [Mlt-devel] [Kdenlive-devel] big changes to consumer_avformat.c - impacts kdenlive

[Dan D. <da...@de...>]

On Wed, Aug 13, 2008 at 3:24 AM, Mads Bondo Dydensborg
<ma...@dy...> wrote:
> onsdag 13 Februar 2008 skrev Dan Dennedy:
>
> I know this is a very old post, that I am responding to, but I have trouble
> getting it to work as expected. Using most recent mlt svn.
>
>> Hey all,
>>
>> With the last commit, MLT just made the jump to real world-class
>> encoding! Be sure to read the exciting notes in the commit message. In
>> summary, you no longer have to remember MLT's special properties for
>> the settings. Now it uses ffmpeg's options which you can look up with
>> 'ffmpeg -h' and 'ffmpeg -formats.' With inigo, you just need to
>> translate ffmpeg's '-option value' syntax to 'option=value.' This also
>> means nearly _all_ of ffmpeg's options are available. Not all of them
>> because some of them only make sense with ffmpeg - e.g. pad and crop.
>
> Up until now, I have used the KDE3 version of kdenlive, and I still am (forced
> to) using it. So, to create DVD's, I have exported a DV file from kdenlive,
> and used this to create VOB files:
>
> ffmpeg -threads 3 -deinterlace -top 0 -i test.dv -target pal-dvd -aspect
> 16:9 -sameq -pass 1 -passlogfile test.log test.mpg
>
> ffmpeg -threads 3 -deinterlace -top 0 -i test.dv -target pal-dvd -aspect
> 16:9 -sameq -pass 2 -passlogfile test.log test.mpg
>
> I am not even sure that is the right way to do it, but it has been giving me
> visually pleasing results.
>
> Now, trying to render directly from the westly file that an export scripts
> from kdenlive0.6 produces, I have tried this command line:
>
> inigo test.westley resize=hyper in=0 out=40206 progress=1 -consumer
> avformat:test.vob deinterlace=1 top=0 target='pal-dvd' aspect=16:9 sameq=1
>
> However, this produces output in a file called "pal-dvd", which is not what I
> expected, and which appears to contain artifacts and has a pretty low bitrate.
> Also, I am very uncertain on how to get multipass. Could you perhaps shed
> some light on this - and why I get a file called 'pal-dvd' in the above
> example?

Not all ffmpeg options are supported. Some are very specific to
ffmpeg.c and not an "AVOption." -target is on example. It is a
convenience option of ffmpeg.c. It some ways it is similar to MLT's
"profile," but does much more. You have to read ffmpeg.c for the
-target processing to see what exactly it sets. Prior to this change,
MLT had already defined its own target property to map to the output
file name. I did not want to introduce a breaking change here and
decided to leave target as is. In some cases, there are ffmpeg.c
options that are not AVOptions which closely resembled an existing MLT
property. In that case, I made MLT support the ffmpeg option name.
Some examples of that are: -s and -ar.

I realize this is rather fuzzy. Maybe I can get a more well-equipped
metadata support in place for this consumer for the next release.
'ffmpeg -h' now clearly reports AVOptions distinct from the
non-AVOption options.  Here is a quick list of non-AVOptions that are
supported:
-f
-b
-r
-s
-aspect
-vcodec
-pass
-passlogfile
-pix_fmt
-aq
-dc
-muxdelay
-muxpreload
-ac
-ar
-atag
-alang
-threads
-qscale
-vtag
-rc_override
-deinterlace
-acodec

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