Gentoo Archives: gentoo-user

From: Kevin O'Gorman <kogorman@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Handbrake: Is it is or is it ain't in portage
Date: Tue, 17 Aug 2010 19:06:03
Message-Id: AANLkTinjdg443dh-FsVLd1z2tRav_6Lw-SA6Yi6Bapo6@mail.gmail.com
In Reply to: Re: [gentoo-user] Handbrake: Is it is or is it ain't in portage by Paul Hartman
1 On Tue, Aug 17, 2010 at 9:06 AM, Paul Hartman
2 <paul.hartman+gentoo@×××××.com<paul.hartman%2Bgentoo@×××××.com>
3 > wrote:
4
5 > On Tue, Aug 17, 2010 at 9:08 AM, Kevin O'Gorman <kogorman@×××××.com>
6 > wrote:
7 > > On Mon, Aug 16, 2010 at 1:21 PM, Paul Hartman
8 > > <paul.hartman+gentoo@×××××.com <paul.hartman%2Bgentoo@×××××.com>> wrote:
9 > >>
10 > >> On Sun, Aug 15, 2010 at 10:02 PM, Kevin O'Gorman <kogorman@×××××.com>
11 > >> wrote:
12 > >> > My underling thing, if anyone can make other suggestions, is that my
13 > >> > camera
14 > >> > broke, and I had to get
15 > >> > one in a hurry, and didn't really know what to look for. I wound up
16 > >> > with a
17 > >> > fairly good Sanyo 1080p camera
18 > >> > and video recorder that's super light, and not too expensive. The
19 > >> > problem
20 > >> > is that its videos are MP4s,
21 > >> > which are definitely not ready to put on a web site, and I know
22 > nothing
23 > >> > about transcoding. My previous
24 > >> > camera took acceptable .avi videos, which had worked with most folks
25 > >> > browsers. The MP4s are huge
26 > >> > and in a weakly supported format.
27 > >>
28 > >> You might want to check out kdenlive which is a full-featured video
29 > >> editor (using mlt as backend) but includes a simple transcoding
30 > >> function and several presets for many different formats (with the
31 > >> added bonus that you'll be able to edit your raw video should you so
32 > >> desire).
33 > >
34 > > Thanks, I emerged kdenlive. I can not open my MP4 files, but I can add
35 > them
36 > > as clips. Okay.
37 > >
38 > > The clips do not play in any reasonable form. I get moments of sound,
39 > and a
40 > > few pixels
41 > > changing on screen; nothing coherent. I'd been told that H264 needs a
42 > lot
43 > > of CPU and I
44 > > guess an old 4-core 32-bit XEON (effectively 800 MHz each) on 2 GB ECC
45 > DDR1
46 > > is not enough. Okay.
47 >
48 > I don't think you'll be able to play back HD video in real-time on
49 > that hardware. Even on, for example, Core 2 at 3GHz playing HD video
50 > used something like 90% CPU (without a hardware mpeg4 decoder).
51 >
52 > > The killer though, is that I cannot figure out how to export that clip in
53 > > some other form.
54 > > And of course, I'm clueless about what form would be optimum. Asking for
55 > > help takes
56 > > me to a forum that has a thread on the topic, but no useful answer.
57 >
58 > You need to add it as a clip, then drag that clip to the timeline in
59 > the lower half of the window. It may take it a while to process once
60 > you've dropped it here (I believe it thumbnails/indexes the video).
61 > It's sort of like a multi-track audio editor, you can overlay effects,
62 > drag the ends of the video clips to change the start/end point, etc.
63 > The more effects you add the slower the encoding will be. For example
64 > I used it on a 5-minute video from my wedding to fade-in and fade-out,
65 > print a title at the beginning, and normalize the audio. I encoded it
66 > to a 720p mp4 which I could then upload to YouTube and let YouTube
67 > re-encode it to lower resolutions for people who can't do HD.
68 >
69 > Once you've got your clip on the timeline, to save as another format
70 > click the "Render" button. In the Render window, you can choose the
71 > output format. It will give you many options such as MPEG-2, XviD,
72 > Flash, RealVideo, Theora etc. You can also adjust the output video
73 > dimensions and bitrate. Hopefully you can find something that will
74 > work for your audience. If you have other video files that worked well
75 > for you in the past, you might check out what their specs are and try
76 > to mimic it.
77 >
78 > It will probably take ages to process, depending on how long your
79 > video is. I have a Core i7 920, overclocked, and encoding a 1440x1080
80 > interlaced video to another format still takes more time than the
81 > length of the video clip (usually 1.5 to 2 times with no effects
82 > added). Since you're dealing with even higher-resolution video and
83 > slower hardware I imagine you're probably looking at overnight, or
84 > days, depending on how much video you're dealing with.
85 >
86 > One "trick" to speed things up is to first transcode your video to an
87 > uncompressed format, and then do all of your editing operations on
88 > that uncompressed file. This requires massive amounts of disk space
89 > and fast disks, though (I think a 5 minute clip was about 70
90 > gigabytes).
91 >
92 > > Is there a kdelive tutorial anywhere? One basic walkthrough and I'd
93 > > probably be able
94 > > to figure out the rest of what I want.
95 >
96 > There are some video tutorials here:
97 > http://www.kdenlive.org/tutorial
98 >
99 > And the user manual has a quick-start section, I believe:
100 > http://www.kdenlive.org/user-manual
101 >
102 > If you don't really need or want HD video, you might also consider
103 > going "old school" and getting a video capture card (which encodes to
104 > something more CPU-friendly like mpeg2). Then you could play the video
105 > on the camcorder and record it onto the computer and let the capture
106 > card do the heavy lifting.
107 >
108 > If kdenlive is a dead end, other alternatives might be:
109 > Install handbrake binaries into your user directory, forgetting about
110 > portage entirely for the moment.
111 > Use ffmpeg if you can figure out the commandline options (I never can)
112 > Other video-converter packages include tovid, though support of HD
113 > video might not be there.
114 >
115 > Good luck!
116 >
117 >
118 Great! Thanks for all that useful information. I think I'll be good from
119 here.
120 I was going to upgrade that 2002 Xeon system anyway (but maybe no right
121 away), but my results now make sense to me, and your information very
122 clear.
123
124 ++ kevin
125 --
126 Kevin O'Gorman, PhD