Newest 'ffmpeg' Questions - Stack Overflow

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• Read raw YUV with ffplay : how to set the colorspace ?

  20 juin 2016, par Ulysse Darmet

  I'm using ffplay on my Ubuntu 16.04 to read raw YUV videos as follows:

  ffplay -f rawvideo -video_size 1920x1080 -colorspace bt2020_cl -color_primaries bt2020 -pixel_format yuv420p10 -i FireEater2Clip4000r1_1920x1080p_25_hf_2020_ct2020_420.yuv
  

  But the video it gives me looks like that

  Instead of being more orange-colored like that

  Does anyone have an idea of what I'm doing wrong ? I'm new to video compression so any help would be appreciated :)

  EDIT: I solved the problem ! This wasn't related to a misuse of ffplay but to my building of the .yuv from the .exr (I forgot to specify the transfer function.)

• FFMPEG with Ubuntu and Multicast UDP Help me

  20 juin 2016, par michell

  good morning! My name is Michael, i'm Brazilian (sorry, my english is very bad :D)

  I'm transmiting by a computer use VLC transport stream about group multicast 239.0.0.1:5001 and receiving by another computer Ubuntu OS using ffmpeg. How i record this transport stream to .ts file with ffmpeg? how i check bitrate of transport stream, null packets and vídeo with ffmpeg?

  Help me, i will buy a chocolate for you haha :D

  Thanks for your support.

  Michaell

• Libavcodec decode ffmpeg Fuzz-testing

  20 juin 2016, par Marso

  I'm implementing a testing stub for libfuzzer. My purpose is to do some testing for libav and I'm currently trying to do it for ffmpeg codec. Testing stub has *data and size as arguments, which are data as file data and size as filze size. Purpose is to open ffmpeg file and decode it.

  I have read decode example from here: http://roxlu.com/2014/039/decoding-h264-and-yuv420p-playback

  I just have problems understanding how should I open and decode file. My code currently looks like this:

  #include 
  #include 
  #include 
  #include 
  
  extern "C" {
  #include "libavcodec/avcodec.h"
  #include "libavutil/avutil.h"
  }
  
  #define INBUF_SIZE 4096
  #define AUDIO_INBUF_SIZE 20480
  #define AUDIO_REFILL_THRESH 4096
  
  
  extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
    avcodec_register_all();
    AVCodec *codec;
    AVCodecContext *c= NULL;
    AVCodecParserContext* parser;
    uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
    FILE *f;
    AVPacket avpkt;
  
    codec = avcodec_find_decoder(AV_CODEC_ID_MP2);
    c = avcodec_alloc_context3(codec);
    parser = av_parser_init(AV_CODEC_ID_MP2);
  
    // decode file
  
  
    av_parser_close(parser);
    avcodec_close(c);
    av_free(c);
  
    return 0;
  }
  

• Converting AC3 to AAC with minimal loss [on hold]

  20 juin 2016, par forthrin

  iPad does not seem to support the ac3 audio codec.

  Therefore, I am converting an mkv/h264/ac3 movie into m4v/m264/aac using ffmpeg to view it on the iPad.

  The video part is simply copied as it is; my question is how I preserve the audio as best possible.

  1. Is there any way to do the audio conversion losslessly?

  2. If no to question 1, what is the best way to preserve the audio quality? If the source audio is 192 kb/s and 48000 Hz, should I simply use 192/48000 for the target too? Or will I preserve the audio better if I increase the the bit rate somewhat?

  3. Side question: I noticed that a lot of mkv files have rather poor audio to begin with. Will the loss of ac3/aac re-encoding be negligable compared to the initial quality loss from the source material? And why isn't high audio quality more of a priority for movie files? It's not like file sizes matter much anymore with today's storage and bandwidth.

• How to integrate a video editor into a web application [on hold]

  20 juin 2016, par Nick Lynch

  I am looking to figure out how to integrate a video editor into an application i'm building, using php (laravel 5).

  I am experienced in php development, and how to play and other front-side aspects of video, but I cannot find much on how to actually edit video on the server side. I have found FFMPEG or Kaltura may be the way to go, but i have found very little about those or if they are the right tools.

  Please let me know the best way to actually implement a video editor into my app

  Thank you!!!