[Matroska-users] Question regarding MKV
ivan.kowalenko at gmail.com
Sat Nov 3 15:36:17 CET 2007
On Nov 2, 2007, at 03.52, Sarreti Balazs wrote:
> If I have a video in MKV with the following details:
> Video #0
> Codec : MPEG-4 AVC
> Codec/Info : MPEG4 ISO advanced profile
> Audio #0
> Codec : AC3
> Is there a fast way to convert/extract the video to the Playstation
> 3 friendly format MPEG-4 AVC?? I used Ultra MP4 Video Converter,
> but this took 8 hours of work. Is there a faster way? Thank you for
> your help and great work!
This actually highlights the main reason Matroska has become so
popular recently. MKV is the only container that supports a large
amount of data (more than 4 GB), H.264 (A.K.A.: MPEG-4 AVC), and AC3
(A.K.A.: Dolby Digital).
The task you're asking is actually simpler than you'd imagine. Your
video (which consumes the most power to transcode) is already in an
appropriate format. The PS3's too picky about AVI, so we can't use
that, and our safest target container is an MP4 file. The MPEG-4
specification doesn't support AC3, so we'll have to transcode that to
something else. Fortunately, transcoding audio shouldn't take nearly
as long as video (I'm actually surprised it took only 8 hours).
I'm going to assume you're running Windows, so I'm going to have to
inform you that I'm dreadfully out of date on Windows tools, so I'm
going to let you know of the tools I understand and am aware of, but
if you know a tool that'll do these things too, you'll be fine.
MEncoder, a mature Linux tool, has a Windows port, but it runs in the
command line, so it might seem intimidating. What we have to do is
passthrough the video, and re-encode the audio. The command line for
MEndcoder would look like this:
mendcoder (input) -ovc copy -oac faac -faacopts
br=192:mpeg=4:object=2 -channels 6 -of lavf -o (output).mp4
Theoretically, that should crank out a video file that ONLY
transcodes the audio, keeps your 6-channel configuration, and dumps
it all to an MP4 file that the PS3 should have no problem with. The
biggest trick in finding a similar app is that most will disgregard
the fact that you're working with a 6-channel (probably 5.1) audio
mix, and just downmix it to stereo (2-channel). Also, many apps don't
seem to allow for passthrough.
VLC can do the job too, but you'll end up with stereo audio, and not
a lot of control options. Still, it might be just what you need.
QuickTime can also do the job, and very well I might add, but I'm not
sure if there's an Matroska Plug-in, or even an AC3 plug-in, for
Windows. I know one exists for Mac OS X (for both plug-ins), but
Windows is a whole other story. QT would be ideal, since it supports
multi-channel AAC, and Apple literally wrote the book on the MPEG-4
specification (the container is based off of Apple's development of
the QuickTime MOV container).
Good luck, man.
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