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• ffmpeg screenshot ISO Files [closed]

  4 mai 2013, par user1825932

  Hi i try to make screenshot of DVD iso file with ffmpeg. With other file type, like avi or mkv, it work fine. I use ffmpeg with ubuntu 10.4 and
  I use this command :

     ffmpeg -ss 0:05:00 -i /home/Videofile -sameq  -vframes 1 -t 00:00:02 -f image2 /home/image1.png

  But with iso file it's not working.
  Any advice ?

  Thanks

  EDIT
  This is the output :

  ffmpeg version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  
    built on Apr  2 2013 17:02:36 with gcc 4.6.3
  
  *** THIS PROGRAM IS DEPRECATED ***
  
  This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
  
  [mpeg @ 0x6207a0] max_analyze_duration reached
  
  /home/Video.iso: could not seek to position 3600.196
  
  Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1) -> 45000.00 (45000/1)
  
  Input #0, mpeg, from '/home/Video.iso':
  
    Duration: 00:01:00.47, start: 0.195667, bitrate: 957672 kb/s
  
      Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [PAR 64:45 DAR 16:9], 9800 kb/s, 25.07 fps, 45k tbr, 90k tbn, 50 tbc
  
      Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
  
  Incompatible pixel format 'yuv420p' for codec 'png', auto-selecting format 'rgb24'
  
  [buffer @ 0x628d60] w:720 h:576 pixfmt:yuv420p
  
  [avsink @ 0x621b80] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
  
  [scale @ 0x6222a0] w:720 h:576 fmt:yuv420p -> w:720 h:576 fmt:rgb24 flags:0x4
  
  Output #0, image2, to '/home/image1.png':
  
    Metadata:
  
      encoder         : Lavf53.21.1
  
      Stream #0.0: Video: png, rgb24, 720x576 [PAR 64:45 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 45k tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  frame=    0 fps=  0 q=0.0 Lsize=      -0kB time=10000000000.00 bitrate=  -0.0kbits/s    
  
  video:0kB audio:0kB global headers:0kB muxing overhead -inf%

• Revision 60244ec1f4 : Dual ARF changes : Buffer index selection. Add indirection to the section of buf

  23 juin 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_bitstream.c

  
   Modify /vp9/encoder/vp9_encoder.c

  
   Modify /vp9/encoder/vp9_firstpass.c

  
   Modify /vp9/encoder/vp9_firstpass.h

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
  
  Dual ARF changes : Buffer index selection.

  Add indirection to the section of buffer indices.
  This is to help simplify things in the future if we
  have other codec features that switch indices.

  Limit the max GF interval for static sections to fit
  the gf_group structures.

  Change-Id : I38310daaf23fd906004c0e8ee3e99e15570f84cb

• FFMPEG Custom Read function reads all the data

  15 juillet 2014, par Hafedh Haouala

  I’m trying to implement a custom read function for ffmpeg that will retrieve a buffer from local video ( from device in the future) and then deocde this buffer, etc..

  So, here’s my read function

  int IORead(void *opaque, uint8_t *buf, int buf_size)
  
  {
  
  FileReader* datrec = (FileReader*)opaque;
  
  int ret = datrec->Read(buf, buf_size);
  
  return ret;
  
  }

  As for the FileReader :

   class FileReader { 
  
   protected:
  
    int fd;
  
   public:
  
    FileReader(const char *filename){ //, int buf_size){
  
        fd = open(filename, O_RDONLY);
  
        };
  
  
  
   ~FileReader() {
  
         close(fd);
  
       };
  
  
  
   int Read(uint8_t *buf, int buf_size){
  
     int len = read(fd, buf, buf_size);
  
     return len;
  
        };
  
   };

  and for the my execution :

  FileReader *receiver = new FileReader("/sdcard/clip.ts");
  
  
  
  AVFormatContext *avFormatContextPtr = NULL;
  
  this->iobuffer = (unsigned char*) av_malloc(4096 + FF_INPUT_BUFFER_PADDING_SIZE);
  
  avFormatContextPtr = avformat_alloc_context();
  
  avFormatContextPtr->pb = avio_alloc_context(this->iobuffer, 4096, 0, receiver, IORead, NULL, NULL);
  
  avFormatContextPtr->pb->seekable    = 0;
  
  
  
  int err = avformat_open_input(&avFormatContextPtr, "", NULL, NULL) ;
  
  if( err != 0)
  
   {...}
  
  // Decoding process
  
    {...}

  However, once the avformat_open_input() is called, the read function IORead is called and keeps reading the file clip.ts until it reaches its end and only then it exit and the decoding process is reached with no data to decode ( as all of it was consumed)

  I don’t know what is the problem especially that this code

   AVFormatContext *avFormatContextPtr = NULL;
  
   int err = avformat_open_input(&avFormatContextPtr, "/sdcard/clip.ts", NULL, NULL) ;

  isn’t blocking untill the end of the file is reached.

  Am I missing something ?
  I appreciate your help.