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• FFMPEG - Converting TS frame to PNG creating invalid images

  20 juillet 2015, par spelley

  I am attempting to snag a single frame from a TS live stream and generate a PNG image. The command I’ve been using is :

  ffmpeg -y -i "filenamehere" -f image2 -vframes 1 -s 250x250 ./snapshot-250x250.png

  When doing this on my local Windows machine using the FFMPEG executable, it generates the image as expected. When using Ubuntu, after doing an apt-get install ffmpeg and using the same command, I am generating grey squares with sporadic noise even while targeting the same file with the exact same command.

  Here is the (anonymized) output :

  [h264 @ 0xa256a0] no frame!
  
  [h264 @ 0xa256a0] non-existing SPS 0 referenced in buffering period
  
  [h264 @ 0xa256a0] non-existing PPS referenced
  
  [h264 @ 0xa256a0] non-existing SPS 0 referenced in buffering period
  
  [h264 @ 0xa256a0] non-existing PPS 0 referenced
  
  [h264 @ 0xa256a0] decode_slice_header error
  
  [h264 @ 0xa256a0] non-existing PPS 0 referenced
  
  [h264 @ 0xa256a0] decode_slice_header error
  
  [h264 @ 0xa256a0] non-existing PPS 0 referenced
  
  [h264 @ 0xa256a0] decode_slice_header error
  
  [h264 @ 0xa256a0] non-existing PPS 0 referenced
  
  [h264 @ 0xa256a0] decode_slice_header error
  
  [h264 @ 0xa256a0] no frame!
  
  [mpegts @ 0xa1d1e0] max_analyze_duration reached
  
  [NULL @ 0xa28080] start time is not set in estimate_timings_from_pts
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 59.94 (60000/1001) -> 1000.00 (1000/1)
  
  Input #0, mpegts, from '<file here="here">':
  
    Duration: 00:00:09.07, start: 35968.174711, bitrate: 697 kb/s
  
    Program 1
  
      Stream #0.0[0x100]: Video: h264 (High), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 44.52 fps, 1k tbr, 90k tbn, 59.94 tbc
  
      Stream #0.1[0x101]: Audio: aac, 48000 Hz, stereo, s16, 96 kb/s
  
      Stream #0.2[0x102]: Data: [21][0][0][0] / 0x0015
  
  Incompatible pixel format 'yuv420p' for codec 'png', auto-selecting format 'rgb24'
  
  [buffer @ 0xa43480] w:1280 h:720 pixfmt:yuv420p
  
  [avsink @ 0xa28780] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
  
  [scale @ 0xa26520] w:1280 h:720 fmt:yuv420p -> w:1280 h:720 fmt:rgb24 flags:0x4
  
  Output #0, image2, to './snapshot-250x250.png':
  
    Metadata:
  
      encoder         : Lavf53.21.1
  
      Stream #0.0: Video: png, rgb24, 1280x720 [PAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 1k tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  frame=    1 fps=  0 q=0.0 Lsize=      -0kB time=0.01 bitrate= -17.6kbits/s dup=31 drop=0
  
  video:8kB audio:0kB global headers:0kB muxing overhead -100.261749%
  
  </file>

  The initial "no frame !" I believe is just it seeking to the first valid keyframe (And thus no cause for concern) however the only difference from my Windows output is the inclusion of this line :

  Incompatible pixel format 'yuv420p' for codec 'png', auto-selecting format 'rgb24'

  Windows has an encoder of Lavc56.46.100 instead of Lavf53.21.1 and the stream mapping line on Windows has more information :

  Stream #0:0 -> #0:0 **(h264 (native) -> png (native))**

  I’ve attempted to manually seek to frames, change the output format from PNG -> GIF, JPEG and just cant seem to find the issue which has no problems on my local Windows machine. Any advice on where to look would be greatly appreciated ! Below is an example of the garbled output.

  

• .mov file not playing on Mac [closed]

  15 août 2023, par evorg88

  I have exported a number of videos from a Bosch CCTV system. These cover a period of 24 hours, and are split into approx. 16 minute clips @ 650MB. The files outputted are of the .mov format.

  


  When I try to open any of these clips, the following happens :

  


  

  • Windows Media Player opens and presents a still image of the first frame, then closes after approx. 3 seconds. It doesn’t allow me to scroll through the video whilst it’s attempting to play.

  


  • QuickTime Player does the same as windows media player.

  


  • VLC allows me to scroll through the video, but doesn’t actually start playing. This also closes after a few seconds.

  


  


  All of the files show approx. 650MB file size, but zero second duration.

  


  I tried using VLC to convert one of the files to an MP4 type, and now it plays without issue !

  


  Note, I then tried converting the original .mov file to MP4 using ffmpeg due to its batch conversion capability, but this failed to output a file that would play.

  


  I understand I’ll need to convert all of the files to MP4 now (although I can’t understand the reason why), but it looks like VLC makes you convert them one at a time.

  


  If anybody can help me out with where I’m going wrong, or advice on a batch conversion method for Mac (M1) it would be hugely appreciated !

  


  Thanks !

  


• avformat/hls : reduce default max reload to 3

  15 mai 2023, par Michael Niedermayer

  avformat/hls : reduce default max reload to 3
  The 1000 did result in the appearance of a never ending reload loop
  The RFC mandates that "If the client reloads a Playlist file and finds that it has not
  
  changed, then it MUST wait for a period of one-half the target
  
  duration before retrying." and if it has changed
  
  "the client MUST wait for at least the target duration before attempting to reload the
  
  Playlist file again"
  Trying to reload 3 times seems a better default than 1000 given these
  
  durations
  Issue found by : Сергей Колесников
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/hls.c