Unix-style video editing (i.e. with pipes, etc.)

JoeyAdams · 03-20-2008, 05:13 PM

Is there a video-editing package available that is similar to something like this?:

Code:

vopen initial.ogg | vcrop -rect 10,10,300,400 | \
  vfilter -brightness +10 | vclose > final.ogg

The purpose of this type of video editing toolchain would be to have a simple and consistent backend upon which graphical video editors could be built in addition to being able to use shell scripting techniques to perform complex video editing tasks.

In my implementation of the idea, vopen decompresses the video and makes it suitable for passing through pipes. vclose recompresses it into ogg. What should happen is that `vopen initial.ogg > initial.yuv' will create a huge file if the initial.ogg is long, but the above code chain won't create such a large memory footprint because data is handled in small amounts at a time due to the nature of pipes. This is similar to the advantage of doing `dd if=/dev/sda1 | gzip > sda1.gz' rather than `dd if=/dev/sda1 of=sda1.img ; gzip sda1.img'.

If such a system hasn't been created yet, what do you suppose the pros and cons of it would be?

JoeyAdams · 03-21-2008, 12:00 AM

Actually, I've rethought my idea. My new idea is that the intermediary data from vopen to vclose (now called vsave) will be references to original video files that will take up a very small amount of space. The previous system would be terrible for complex actions, as it would require a lot of waiting and would have the overhead of piping all that data by-value. Therefore, in something like this:

Code:

vopen in.ogg > v #opens video and stores it to clip file v
cat v | vclip 0.3s 2s > a #clips out seconds 0.3 to 2 of v into a
cat v | vclip 3s 4.001s > b #clips out seconds 3 to 4.001 of v into a
cat a b | vsave > out.ogg #combines the clips of a and b and saves them to out.ogg

It will create tiny reference files that can be operated on quickly before the save.

simplicissimus · 03-21-2008, 10:04 AM

Tools like mplayer, mencoder, ffmpeg, tovid are those you might want to check first. Mplayer has options to cut out slices from video files and/or separating or replacing audio channels. I'm not sure if it does cropping and zooming as well, but if you really want to go into video editing, then mplayer surely is a good place to start or at least to see how they have implemented the core functionality.

For some reason video editing is not very strong on Linux. Any development you do in this area is welcome. Give feedback on your proceedings.

Regards,
SIMP

Fedora Development

JoeyAdams · 03-21-2008, 02:17 PM

Indeed, those programs do have a lot of the core functionality, and they would be excellent resources for the code needed for the project I'm talking about. However, the biggest weakness (in my opinion) is that you have to explicitly state the -ovc, -oac, and options (no automatic determination for, e.g., -wmv, -ogg, -flv). Also, I think the biggest weakness of video editing in Linux in general is that the only viable solutions seem to be weakly-coded GUIs, well-developed ones with poor backends, and/or confusing interfaces. By having a straightforward video editing backend, it could encourage the creation of a wide variety of open source video editing utilities.

Thanks for the input. I'm still developing my ideas. I'll try to post a design document soon and maybe even restart this thread in the Programming section.