Murray,
On 19/01/12 08:52, Murray Strome wrote:
*Thanks to David, Haldun and Felix for their comments and suggestions.
See my comments below.
------
David Armstrong /<[email protected]>/* wrote:
Murray,
As per Felix and Haldun's reply, the trick is to transcode the raw
video into a codec that Cinelerra likes.
*Haldun ALTAN /<[email protected]>/* wrote:
Hello,
I'm on Ubuntu studio 10,04 / 64 and I use EKD (you can get it from
synaptics) to transcode HD files on DNxHD to use them in cinelerra. It
works OK. (sound and images.) Then follow instruction on Grandma to
render in best quality. For me it works.
Haldun
It took me a while to figure out how to download and install EKD. It
appears that it is only available in French. However, I did find some
English documentation on the internet. Nevertheless, I have found that
my .mp4 video shows up with weird colours (skin tones are
blue/green). I see this is also the case in some video viewers, such
as VLC. They are OK in Gnome Player, and some others. Thus, I
reverted to using ffmpeg. If I remember correctly, I did something like:
$>ffmpeg -i {input_file.mp4} -b 8500k -s hd1080 {outputfile.mov}
and it seemed to work OK (the q factor seemed to be around 8 -- I
would prefer to get it down to 2). The resulting file looks good in
Gnome Player, and also in my Windows software. However, when I load it
into Cinelerra, in the compositor it only shows a central section of
the video. It looks OK on the timeline, and the colours look fine. I
tried playing with things like zoom, project preferences, etc. but
could not get the compositor to show the full frame -- any idea what I
am missing there?
*check the size of the display - you can decrease/increase the display
size. Sounds like you have the window smaller than the display size.*
*If the output is Ok then you must have selected the right video size
(eg 1280x720)*
--------
*felix /<[email protected]>/* wrote:
Hi Murray
My work flow with Cinelerra first involve converting my video files to
an intermediate codec: Mjpeg. I use the program ffmpeg with a command
line similar to:
ffmpeg -i input_file -vcodec mjpeg -qscale 0 -s 1920x1080 -pix_fmt
yuvj420p -acodec copy output_file
I use a .mov extension for the output file
I then load the files in Cinelerra and edit them.
For rendering I use the following settings:
File format: Quicktime for Linux
audio track rendering: Twos complement, 16 bits
Video: YUV 4:2:0 Planar
This produces very large files, of about 4 Gig/ minute for 1080p
I then use ffmpeg again to convert the video to a format that I
will use
elsewhere.
For instance to upload video on vimeo and covert it to 720p, I use
ffmpeg -i input_file -vcodec libx264 -vb 2000k -s 1280x720 -acodec
libmp3lame -ab 256k output_file
This work flow has been working for me, you can experiment with
different settings in terms of codecs, bitrate, qscale and others
settings to get the file format that you need.
There is also the Arista transcoder to convert files from one
format to
an other. It has presets for common displaying means: pc, tablet,
phones, etc.
Hope it helps
Félix-A.
Thanks for your hints, Felix. I will have to try to learn
(relearn???) what options to use for ffmpeg. However, using the
settings above and outputting to .MOV looks like a good, easy first
step if I could only figure out why it seems to show only the central
section of the video in the compositor, I could begin to try to use it.
- - - - -
For 720p, I convert the video to quicktime format and dnxhd codec (see
Grandma for details). Cinelerra doesn't like non-standard video
aspects, so also make sure they are standard 1280x720 or 1920x1080
etc. It will accept ".mts", but that is transport stream with a long
GOP format, which can cause various issues of sync'ing and applying
effects. Converting from a long GOP to a non-GOP format will obviously
gobble up more disk space, but that is the trade-off for quality and
stability in editing.
For large or complex projects, I will render a block of video and
import into a parent project. But to do this, the rendering has to be
as high as possible to prevent obvious degradation. Render to
quicktime with MJPEG is what I use there.
Is this with Cinelerra, or with ffmpeg? If the latter, could you
please give me an example of your ffmpeg command to do this? Thanks.
*This is with cinelerra. Select Quicktime For Linux as container, then
MJPEG (or YUV Planar as otherwise suggested) for codec. *
On final render, you choose whatever is appropriate. For the web, I
will output to quicktime with mpeg-4 vid and audio codecs. This is a
good balance between quality and size. I read with interest the format
Felix uses for output (so many options). And FFMPEG is really useful,
but another tool that has so many strings.
As others point out, there is a lot of flexibility that will cause
grief when you get it wrong. Keep experimenting, and when you
understand the control you have, the possibilities are endless.
cheers
David
Thanks again for the replies.
Murray
