FFMPEG - Loop input video

[frifox]

My input source is PNG image (image.png) and MP3 audio (audio.mp3). Currently I loop PNG input to make the video and stream-copy the audio, into the final video (final.avi):

ffmpeg -loop_input -f image2 -i image.png -r 1 -vcodec flv -i audio.mp3 -acodec copy -g 10 -qscale 2 -cmp 3 -subcmp 3 -mbd 2 -flags trell final.avi -shortest

if the image for example is 1024x768, the encoding speed is sub 1FPS! I want to improve the total encoding time by first encoding 5 frames (1 keyframe with the following 4 frames), and then loop copy that video stream into final AVI, say 5 minute video. How can I achieve this?

Thanks in advance!

[45tripp]

Not with ffmpeg alone.

you'd need to find a command line tool to concatenate avi's:
create the section of video with ffmpeg,
concatenate X amount of times based on audio duration (script it),
mux audio and video.

not exactly simple

gl

[bbakersmith]

Use Mencoder.

Concatenating / appending is super easy with Mencoder, check out the following example (for linux or mac):

mencoder -oac copy -ovc copy -o 'output_filename.avi' 'clip1.avi' 'clip2.avi' 'clip3.avi'

Of course, in your case you would be appending the same thing over and over, in which case I would recommend either using a script to generate an appropriate Mencoder command, or using an Avidemux script.

For more on appending clips with Mencoder (including a script example) check out this post:
http://backstar.com/blog/2009/11/10/append-videos-with-mencoder/

Explaining Avidemux scripting is really not in the scope of this reply, but basically you'd just need to use a simple Javascript loop. For example (this will concatenate a clip of 1000 frames 100 times):

for(var f = 0; f < 100; f++) {
  app.addSegment(0,0,1000);
}

To use the above code, do the following:

• open the clip you want to repeat in Avidemux
  save the project file
  open the project file with a text editor
  add the for... code around the app.addSegment() part of the code
  delete the markerA=; and markerB=;
  save the project file
  open the project file in Avidemux
  save the video

That might seem like a lot, but trust me, it's much easier than appending the same file 1000+ times, and much quicker than letting ffmpeg take its sweet time to convert every frame from the original image.

EDIT: oh yeah, then you'll have to mux the audio and video. you can do this with a whole lot of programs, but i'd suggest using ffmpeg if you're willing to deal with the command line (which you probably are if you followed the above instructions)