Re: [gentoo-user] Handbrake: Is it is or is it ain't in portage

[Paul Hartman]

On Tue, Aug 17, 2010 at 9:08 AM, Kevin O'Gorman <kogorman@×××××.com> wrote:
> On Mon, Aug 16, 2010 at 1:21 PM, Paul Hartman
> <paul.hartman+gentoo@×××××.com> wrote:
>>
>> On Sun, Aug 15, 2010 at 10:02 PM, Kevin O'Gorman <kogorman@×××××.com>
>> wrote:
>> > My underling thing, if anyone can make other suggestions, is that my
>> > camera
>> > broke, and I had to get
>> > one in a hurry, and didn't really know what to look for.  I wound up
>> > with a
>> > fairly good Sanyo 1080p camera
>> > and video recorder that's super light, and not too expensive.  The
>> > problem
>> > is that its videos are MP4s,
>> > which are definitely not ready to put on a web site, and I know nothing
>> > about transcoding.   My previous
>> > camera took acceptable .avi videos, which had worked with most folks
>> > browsers.  The MP4s are huge
>> > and in a weakly supported format.
>>
>> You might want to check out kdenlive which is a full-featured video
>> editor (using mlt as backend) but includes a simple transcoding
>> function and several presets for many different formats (with the
>> added bonus that you'll be able to edit your raw video should you so
>> desire).
>
> Thanks, I emerged kdenlive.  I can not open my MP4 files, but I can add them
> as clips. Okay.
>
> The clips do not play in any reasonable form.  I get moments of sound, and a
> few pixels
> changing on screen; nothing coherent.  I'd been told that H264 needs a lot
> of CPU and I
> guess an old 4-core 32-bit XEON (effectively 800 MHz each) on 2 GB ECC DDR1
> is not enough.  Okay.

I don't think you'll be able to play back HD video in real-time on
that hardware. Even on, for example, Core 2 at 3GHz playing HD video
used something like 90% CPU (without a hardware mpeg4 decoder).

> The killer though, is that I cannot figure out how to export that clip in
> some other form.
> And of course, I'm clueless about what form would be optimum.  Asking for
> help takes
> me to a forum that has a thread on the topic, but no useful answer.

You need to add it as a clip, then drag that clip to the timeline in
the lower half of the window. It may take it a while to process once
you've dropped it here (I believe it thumbnails/indexes the video).
It's sort of like a multi-track audio editor, you can overlay effects,
drag the ends of the video clips to change the start/end point, etc.
The more effects you add the slower the encoding will be. For example
I used it on a 5-minute video from my wedding to fade-in and fade-out,
print a title at the beginning, and normalize the audio. I encoded it
to a 720p mp4 which I could then upload to YouTube and let YouTube
re-encode it to lower resolutions for people who can't do HD.

Once you've got your clip on the timeline, to save as another format
click the "Render" button. In the Render window, you can choose the
output format. It will give you many options such as MPEG-2, XviD,
Flash, RealVideo, Theora etc. You can also adjust the output video
dimensions and bitrate. Hopefully you can find something that will
work for your audience. If you have other video files that worked well
for you in the past, you might check out what their specs are and try
to mimic it.

It will probably take ages to process, depending on how long your
video is. I have a Core i7 920, overclocked, and encoding a 1440x1080
interlaced video to another format still takes more time than the
length of the video clip (usually 1.5 to 2 times with no effects
added). Since you're dealing with even higher-resolution video and
slower hardware I imagine you're probably looking at overnight, or
days, depending on how much video you're dealing with.

One "trick" to speed things up is to first transcode your video to an
uncompressed format, and then do all of your editing operations on
that uncompressed file. This requires massive amounts of disk space
and fast disks, though (I think a 5 minute clip was about 70
gigabytes).

> Is there a kdelive tutorial anywhere?  One basic walkthrough and I'd
> probably be able
> to figure out the rest of what I want.

There are some video tutorials here:
http://www.kdenlive.org/tutorial

And the user manual has a quick-start section, I believe:
http://www.kdenlive.org/user-manual

If you don't really need or want HD video, you might also consider
going "old school" and getting a video capture card (which encodes to
something more CPU-friendly like mpeg2). Then you could play the video
on the camcorder and record it onto the computer and let the capture
card do the heavy lifting.

If kdenlive is a dead end, other alternatives might be:
Install handbrake binaries into your user directory, forgetting about
portage entirely for the moment.
Use ffmpeg if you can figure out the commandline options (I never can)
Other video-converter packages include tovid, though support of HD
video might not be there.

Good luck!