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• FFmpeg command help and pointers for documentation

  27 novembre 2011, par mahi

  I was working with FFmpeg for one of my android project. So far, I have been able to successfully able to compile FFmpeg for ARM. Now my approach is to write a JNI interface for playing videos using FFmpeg.

  I tried executing the command ./ffmpeg --help to see the options available with FFmpeg, and so far I am only able to understand that the input filename can be provided with -i fileName option.

  I have been searching for online tutorials / blogs for FFmpeg commands, and how to play a video / RTMP stream, but couldn't find a suitable link.

  I'd like to know the following :

  1. What is the command to play a video using FFMpeg ?
  2. What is the command to play a local file using FFMpeg
  3. What is the command to play a RTMP stream using FFMpeg
  4. Java / C sample code to play video using FFMpeg
  5. Is it possible to extract some piece of code from ffplay.c and write a custom code ?

  Any help with the above and / or any pointers to relevant links is highly appreciated.

  Thanks.

• How to optimize video to animated GIF conversion using PHP + shell commands

  15 mars 2012, par user1070798

  I have a web application that converts any video into an animated GIF. The app runs in PHP and the following steps are executed through php's shell_exec :

  1. Scale video to smaller dimensions, if they are large (ffmpeg -i $in -s 200x150 -an $out)
  2. Use ffmpeg to extract 1 jpeg every x seconds (ffmpeg -i $in -ss $ss -vframes 1 $out)

  3. Convert jpegs to animated GIF using imagick (convert -delay $delay -loop 0 $dir/* $out)

     aside - the reason I don't use the ffmpeg gif89a output is because the quality sucks.

  I want to be able to except any major image format, but the most common will probably be .flv (flash) and .avi/.mpg.

  My application runs fine, but I am a perfectionist and it needs to be faster for scalability.

  My web server has 16 cores and I would like to utilize them as much as possible, but .flv multi-threading appears to not be supported by ffmpeg, while .avi and some others are supported. Also, ffmpeg doesn't support multi-threading when outputting to jpegs.

  Does anyone know of any other programs that support multi-threading for .flv and others ? Are there any more efficient methods to create an animated GIF from video, while maintaining relatively decent quality (aka not the 100-color palette that ffmpeg supports) ?

  Also, if anyone knows which codecs might perform best for stages 1 and 2, particularly with flv, I'd love to know. I've done hours of testing, but there are just so many options I haven't come to any solid conclusions.

  ***Update : My online app is working well so far animated gif generator. I would still love to make it faster though, so if anyone has run into similar circumstances... let me know !

• Where can I find modern tutorials for libav, ffmpeg, etc ? [on hold]

  19 décembre 2016, par Marty

  I want to make a quick program in C that will open a video, save each frame as a ppm, and dump motion vectors. All the tutorials I can find are from almost ten years ago and call deprecated or non-existent functions.

  Are there any good online resources, websites, videos, or textbooks that cover a modern approach to doing these types of things ?