Newest 'ffmpeg' Questions - Stack Overflow

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• What are the APIs for hardware accelerated video decoding in phones ?

  11 janvier 2012, par cloudraven

  I have seen many smartphones coming with hardware accelerated video decoding supporting mpeg2 and h264, but unlike in desktop and laptop systems, it is not clear to me how to interact with the hardware acceleration. For desktops/laptops there is DXVA, VDPAU and OpenMax. Is any of those supported in Mobile phones? I think OpenMax is, but I am not sure of how widely supported it is.

  Is anyone familiar with what is usually used to write hardware accelerated media players and decoders for platforms like Snapdragon, Tegra 2 or Omap 4 running Android or Windows Phone? I know that ffmpeg can be compiled for arm and I wonder what kind of hardware video acceleration it supports on that platform.

• Problem in FFMPEG encoding decoding with IPhone os 4.3 SDK

  11 janvier 2012, par IPhoneUprise

  I want to convert my mov file (audio + video) in to mp4 to reduce file size in IPhone. I successfully compile FFMPEG libraries for armv7 for IPhone OS 4.3 sdk and i was able to decode and encode video frames in IPhone. Now my compressed file size reduced from 48 mb mov file to 2 mb mp4 file.But the audio is missing in compressed mp4 file, so now i am trying to decode and encode audio as well but i am getting issues to integrate this audio encode decode code with my existing code. If any one has any sample which shows how to encode decode audio with video that would be great.

• ffplay/ffmpeg on RTMP with H264-encoding

  11 janvier 2012, par Yuval A.

  I'm trying to play an RTMP encoded with h264 using the Flash Player 11 h264 encoder - with ffplay.

  It works. But only if the stream is set with a bitrate of 64KB and the keyframe interval is 4.
  Otherwise it cant find any frames.

  Any ideas why?

• Extract audio amplitude from video

  11 janvier 2012, par Andrew

  I need to process >200 videos by getting several snapshots from each one. Each snapshot will be taken if the volume is higher than 'x'. So I can make snapshots with FFMPEG but I don't know how to extract the amplitude graph. How can I get an array with the audio volume of each frame?

• Build FFMPEG with x264 error

  11 janvier 2012, par Kage

  I am trying to build FFMPEG with libx264.

  I can successfully build and use FFMPEG for Android but I realized that I need the ability to encode, therefore I am trying to build FFMPEG with x264.

  When trying to build FFMPEG I get an error:

  "ERROR: libx264 not found"

  And in my log it says:

  "/usr/local/lib/libx264.a: could not read symbols: Archive has no index; run ranlib to add one..."

  I have the latest versions of both FFMPEG and x264. I understand that FFMPEG looks for the header and libraries in usr/lib and usr/include, so in order to make it find x264 I use the cflags and ldflags:

  • --extra-cflags = " -I/usr/local/include "
  • --extra-ldflags = " -L/usr/local/lib "

  I have tried building x264 with many different options that other people on the internet have said that i need. eg. --enable-shared, --enable-static, --disable-pthreads etc. Some forums say enable this, others say no disable that.

  Any help would be much appreciated, Thanks