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• avformat/swfdec : Use side data to communicate w/h changes to the decoder

  2 septembre 2014, par Michael Niedermayer

  avformat/swfdec : Use side data to communicate w/h changes to the decoder
  Fixes reading from freed data
  
  Fixes part of Ticket3539
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/swfdec.c

• Remux mp4 file containing data stream

  13 novembre 2020, par Maxito

  I’m developing an app that needs to clone an MP4 video file with all the streams using FFmpeg C++ API and have successfully made it work based on the FFmpeg remuxing example.

  



  This works great for video and audio streams, but when the video includes a data stream (actually a QuickTime Time Code according to MediaInfo) I get this error.

  



  Output #0, mp4, to 'C:\Users\user\Desktop\shortOut.mp4':
    Stream #0:0: Video: hevc (Main 10) (hev1 / 0x31766568), yuv420p10le(tv,progressive), 3840x2160 [SAR 1:1 DAR 16:9], q=2-31, 1208 kb/s
    Stream #0:1: Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, s16p, 32s
    Stream #0:2: Data: none (tmcd / 0x64636D74), 0 kb/s
[mp4 @ 0000000071edf600] Could not find tag for codec none in stream #2, codec not currently supported in container


  



  I’ve found this happens in the call to avformat_write_header().

  



  It makes sense that if FFmpeg doesn’t know the codec it can’t write to the header about it, but I found out that using the ffmpeg command line I can make it to work perfectly using the copy command for the stream, something like :

  



  ffmpeg -i input.mp4 -c:v copy -c:a copy -c:a copy output.mp4


  



  I have been analyzing ffmpeg.c implementation to try to understand how they do a stream copy, but it’s been very painful following along the huge pipeline.

  



  What would be a proper way to remux a data stream of this type with FFmpeg C++ API ? Any tip or pointers ?

  


• JSON Python check for data

  3 mars 2017, par Georgе Stoyanov

  So I am trying to write a script which is looking into a JSON file and check if stream with index 1 exists. Right now my program doesn’t do that. Here is the program itself. I want to check if (data["streams"][1]) exists and in case it exists to print the codec, sample rate and the bitrate of all available audio streams.

  #!/usr/bin/env python
  
  import subprocess
  
  import json
  
  import os.path
  
  
  
  # Saving the file path and the name path into input_file
  
  
  
  input_file = raw_input("Please enter the input file path: ")
  
  
  
  # Loop until the user enters a valid input file
  
  
  
  while os.path.isfile(input_file) == False:
  
          print "Please try again, the specified file / path don't exist!"
  
          input_file = raw_input("Please enter the input file path again: ")
  
  
  
  # Execution of the ffprobe command to list the general statistics of the file. I have separated both scripts because the script for analyzing the frames is taking longer time.
  
  
  
  returned_data = subprocess.check_output(['ffprobe', '-v', 'quiet', '-print_format', 'json', '-show_format', '-show_streams', input_file])
  
  
  
  # Loading of the json file
  
  
  
  data = json.loads(returned_data.decode('utf-8'))
  
  t = (data["streams"][0]["avg_frame_rate"])
  
  fps = [float(x) for x in t.split('/')]
  
  
  
  # Printing of the general information about the video file
  
  
  
  print "========================== Video ============================="
  
  print
  
  print "Codec: %s" %(data["streams"][0]["codec_long_name"])
  
  print "Profile: %s" %(data["streams"][0]["profile"])
  
  print "Resolution: %d x %d" %((data["streams"][0]["width"]), (data["streams"][0]["height"]))
  
  print "Pixel Format: %s" %(data["streams"][0]["pix_fmt"])
  
  print "Bits per sample: %s" %(data["streams"][0]["bits_per_raw_sample"])
  
  print
  
  print "========================== Audio ============================="
  
  print
  
  print "Codec: %s" %(data["streams"][1]["codec_name"])
  
  print "Sample Rate: %.3f KHz" %(int(data["streams"][1]["sample_rate"])/1000)
  
  print "Bitrate: %d Kbps" %(int(data["streams"][1]["bit_rate"])/1000)

  And here is the output of the JSON file.

  {
  
      "streams": [
  
          {
  
              "index": 0,
  
              "codec_name": "mpeg4",
  
              "codec_long_name": "MPEG-4 part 2",
  
              "profile": "Simple Profile",
  
              "codec_type": "video",
  
              "codec_time_base": "1/24",
  
              "codec_tag_string": "FMP4",
  
              "codec_tag": "0x34504d46",
  
              "width": 854,
  
              "height": 480,
  
              "coded_width": 854,
  
              "coded_height": 480,
  
              "has_b_frames": 0,
  
              "sample_aspect_ratio": "1:1",
  
              "display_aspect_ratio": "427:240",
  
              "pix_fmt": "yuv420p",
  
              "level": 1,
  
              "chroma_location": "left",
  
              "refs": 1,
  
              "quarter_sample": "false",
  
              "divx_packed": "false",
  
              "r_frame_rate": "24/1",
  
              "avg_frame_rate": "24/1",
  
              "time_base": "1/24",
  
              "start_pts": 0,
  
              "start_time": "0.000000",
  
              "duration_ts": 14315,
  
              "duration": "596.458333",
  
              "bit_rate": "2500431",
  
              "nb_frames": "14315",
  
              "disposition": {
  
                  "default": 0,
  
                  "dub": 0,
  
                  "original": 0,
  
                  "comment": 0,
  
                  "lyrics": 0,
  
                  "karaoke": 0,
  
                  "forced": 0,
  
                  "hearing_impaired": 0,
  
                  "visual_impaired": 0,
  
                  "clean_effects": 0,
  
                  "attached_pic": 0,
  
                  "timed_thumbnails": 0
  
              }
  
          },
  
          {
  
              "index": 1,
  
              "codec_name": "ac3",
  
              "codec_long_name": "ATSC A/52A (AC-3)",
  
              "codec_type": "audio",
  
              "codec_time_base": "1/48000",
  
              "codec_tag_string": "[0] [0][0]",
  
              "codec_tag": "0x2000",
  
              "sample_fmt": "fltp",
  
              "sample_rate": "48000",
  
              "channels": 6,
  
              "channel_layout": "5.1(side)",
  
              "bits_per_sample": 0,
  
              "dmix_mode": "-1",