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• Find and remove multiple audio tracks in video using ffmpeg

  14 février 2016, par Jaimin Patel

  I have 1 video which has multiple audios in it. There are some dialogues and few different soundtracks. But, when i use ffmpeg -i 1.mp4 it shows only 2 streams.

  Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 2964 kb/s, 24 fps, 24 tbr, 90k tbn, 48 tbc (default)

  Stream #0:1(und) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)

  Its showing only 1 audio stream, If i remove that stream whole video will be mute. But, i only want to remove particular soundtrack from video, and its not showing separate audio stream for different soundtracks and dialogue used in video.

• Unable to find a suitable output format for : Invalid argument

  17 février 2016, par Edgar Canul

  Grettings.
  I’ve read another questions for this problem, but they are instruction-specific issues. Here’s mine :

  ffmpeg -ss 118 -i E :\PF2015\VUELO_1\Video1hd.mp4 -t 6 -codec copy E :\H61005 Git\H61005\reportes\testSnaps\videos\hdVideo121_3.mp4

  The surprise is that I had used this instruction to extract a video fragment (from 118 to 124 secs) and it worked fine. Suddenly it stopped working.

• How to find the actual size occupied by an AVFrame ?

  23 septembre 2013, par jsp99

  The main task at hand is to find the actual size of a decoded AVFrame.

  Here is some background information about the problem -
  I wrote a program which takes as input a media file and displays all the video frames of the file, on the screen. My Code (written in C using SDL and ffmpeg) worked perfectly with .wmv files. When it came to .mkv files, it failed (SIGSEGV) due to the following reason :

  Example : Suppose I have a decoded frame from my video stream of file (filename.mkv) in AVFrame *pFrame. The frame has a pix_fmt (pFrame->pix_fmt) of yuv420p. It has dimensions 640 * 346. The Y-plane has it's linesize (pFrame->linesize[0]) as 672.

  I think you get the point here. When I use avpicture_get_size() to get the size of the frame, it calculates a wrong size. It takes pix_fmt, width and height as arguments. Nowhere does it consider 672 instead of 640.

  avpicture_get_size() : Calculates the size in bytes that a picture of the given width and height would occupy if stored in the given picture format.

  I got around this problem by adding some yuv420p frame specific code, which can find the size of the frame in situations like above.

  • Can someone explain why are most of the decoded frames (from video streams of most of the formats) this way ? And why is it not this way with the wmv format ?

  But if I have to find the actual size occupied by an AVFrame of another format (Eg: yuv410p), I have to write the format specific code again. Coming to the main problem,

  • How can I find the actual size occupied the decoded AVFrame (size in bytes occupied by the data of the AVFrame) ?

  • I tried using av_image_get_buffer_size(), but I couldn't understand how to use the align parameter. Can someone explain the usage of the parameter align ? Tried using many other functions in pixdesc.c, but I am missing something.