1) install gimp-plugin-registry and icc-profiles from the apt repository (“sudo apt-get install gimp-plugin-registry icc-profiles” or use the software centre);
2) open the image I want to send to the print shop and select “Image/Flatten Image” (if the image has multiple layers) and then “Image/Separate/Separate”;
3) in the dialog, accept the default options, but optionally check “Make CMYK pseudo-composite” (this doesn’t seem to affect the final product, but it does generate an image with the colour layers blended in a way that is recognizable — that way you can see that you are getting what you expect);
4) when the new separated version of the image pops up in a new window, select “Image/Separate/Export…” and save as a TIF file;
5) use “tiff2pdf filename.tif -o filename.pdf” to create the pdf file for the printer.

The most useful info I found on this topic was here: https://wiki.archlinux.org/index.php/CMYK_support_in_The_GIMP and http://ian-pullen.suite101.com/how-to-save-cmyk-images-in-gimp-a107979.

This thread explains why my m2t files show up as 1440×1080 even though they can be edited as 1920×1080 (aka 1080i). It has to do with square vs. rectangular pixels — or something — it doesn’t really matter. More general info on formats is here.

In Cinelerra, you must set the project format to 1440×1080, 16:9 ratio, then make sure you select “match output size” by right-clicking on the video track(s). This looks okay in the compositor window in Cinelerra, but the resulting file plays by default at 4:3 aspect ratio. You can set this manually when you open the video in VLC and see that everything looks okay. The only method I have found so far for getting the rendered video to play as 16:9 by default is by using a command such as this on to re-encode it after the fact:

For rendering in various formats, follow the instructions here as usual.

To do the synchronization, I’m using the php uploader found here. It seems to be working, although I had some trouble at first pointing it at the right directory on my system. Running the upload program is simple:

NOTE: I initially had a little trouble because I was pointing to the wrong level in the hierarchy of my picture directory tree. The program assumes an arrangement something like this:

home
user
photo_library
category
album
image.jpg


My reading of the instructions implied that you could point to “/home/user/photo_library/category” but that doesn’t work. You need to point to “/home/user/photo_library.”

Encoding for the Web

To make a tiny file, you can encode files this way:

For better quality output, there are a number of variables you can control. I’m starting with two assumptions for the time being: I’m using the h264 codec and my target output format is mp4. For YouTube, flv would be better.

“-i foo.dv” just identifies the input file, and the rest of the options apply to the output file.

For my own future benefit, I will break down the options I’ve used: “-ab 128k” is the audio bitrate, “-ar 44100″ is the audio sampling frequency (44100 is the default anyhow); “-b 1200k” is the video bitrate; “-vc h264″ is the video codec; “-qscale 1″ sets the video quantizer scale (lower is better quality, use “-sameq” for the same quality); “-s 480×360″ is the target width and height. All of these variables can be changed to create a higher/lower quality file which is smaller/larger in size. These settings create a decent output file for people to download, but it will be resampled on uploading to websites for streaming.

FFMPEG Tricks

If you just want to do a quick trim of the clip before uploading, I’ve found this is an easy way to do it. First play the video:

Note the start and end points you want, then run the ffmpeg command with “-ss NN” for the starting point in seconds and “-t NN” for the duration. That allows you to trim either the start or end of the clip without having to break out Cinelerra or Kino. By the way, I’ve got a pile of switches enabled on mplayer, but the only one that really matters is “-osdlevel 3″ so you can see the counter.

Some Youtube guidance on formats here: http://www.google.com/support/youtube/bin/answer.py?answer=132460&safe=off

Facebook format details are found here. You could use this command and vary the qscale and bitrate to get a reasonable file size:

Vimeo format recommendations give specific values for bit rates and codecs as follows for high quality:

For HD video on Vimeo:

“-s hd720″ tells ffmpeg to create 1280×720 output.

Sources of Information

This video is a good ffmpeg intro: http://www.linuxjournal.com/video/linux-howto-video-editing-magic-ffmpeg

For Youtube uploads, they use the following command. The presenter explains that these parameters are good for Youtube because they will not be re-encoded on upload:

He also shows how to crop and letterbox using ffmpeg and even creates a moving spotlight. He also uses the “-loop_input” ffmpeg switch in order to make a 10 second clip of a still frame. Very handy!

Here is an explanation of how to use ffmpeg for screencasting.

as discussed here: http://linux.byexamples.com/archives/229/extract-audio-from-video-or-online-stream/

UPDATE: To extract wav audio data from a dv file, I had to use this command:

Details here: http://www.tuxradar.com/content/ffmpeg-made-easy

Thanks to Western Arctic Moving Pictures for hosting the workshop!

In the process, I’ve learned a bit about the xml format which Cinelerra uses to store references to files and edits. When you add a resource, it appears twice between opening and closing “ASSET” tags with the format <ASSET SRC=”/path/to/filename”>[asset details]</ASSET>. Then every time you include that file in a track of your project, the filename appears again in an “EDIT” tag complex in the format <FILE SRC=”/path/to/filename”>[edit details]</FILE>

First, I needed to check the paths for all the resources in the file to make sure they are still valid. I called this program test_xml_paths.sh. I corrected the incorrect paths with a text editor, but found that Cinelerra was still crashing with a memory error when I loaded the project.

Second, I decided to find and eliminate all of the unused assets in the file. I originally had a forty minute video in one file, but some time ago I split the project into four ten minute chunks. When I created the original project, I had added a couple of thousands of clips for possible inclusion, so now that I’m working on the final cut, I don’t need all that bloat.

I created a function to figure out which assets were being used in the edit list and which were not: list_unused_assets.sh.

Finally, I wrote a script which would recreate a new xml project file with all the redundant assets removed: remove_unused_assets.sh.

I can’t offer any warranty on these scripts, of course, but I hope they may help somebody else. If nothing else, there’s a great example of multi-line sed editing in the last one.

Save this script as “remove_unused_assets.sh”. It needs the function in “list_unused_assets.sh” which I posted here.

This program depends on include.inc which contains the following:

I tried to make these scripts as tidy and portable as possible — you will, however, need to change the path for $SCRIPTDIR to the location you are using (and $TMPDIR if you don’t want to put your temporary files in /tmp).

Running this script doesn’t do anything until you call the enclosed function. This function can be called from the command line with:

This program depends on include.inc which contains the following:

I tried to make these scripts as tidy and portable as possible — you will, however, need to change the path for $SCRIPTDIR to the location you are using (and $TMPDIR if you don’t want to put your temporary files in /tmp).

This program depends on include.inc which contains the following:

I tried to make these scripts as tidy and portable as possible — you will, however, need to change the path for $SCRIPTDIR to the location you are using (and $TMPDIR if you don’t want to put your temporary files in /tmp).