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• hwcontext_vaapi : remove duplicate formats from sw_format list

  24 juillet 2020, par Haihao Xiang

  hwcontext_vaapi : remove duplicate formats from sw_format list
  hwcontext_vaapi maps different VA fourcc to the same pix_fmt for U/V
  
  plane swap cases, however duplicate formats are not expected in sw_format
  
  list when merging formats.
  For example :
  
  ffmpeg -loglevel debug -init_hw_device vaapi -filter_hw_device vaapi0 \
  
   f lavfi -i smptebars -vf \
  
  "hwupload=derive_device=vaapi,scale_vaapi,hwdownload,format=yuv420p" \
  
   vframes 1 -f null -
  Without this fix, an auto scaler is required for the above command
  
     Duplicate formats in ff_merge_formats detected
  
     [auto_scaler_0 @ 0x560df58f4550] Setting 'flags' to value 'bicubic'
  
     [auto_scaler_0 @ 0x560df58f4550] w:iw h:ih flags :'bicubic' interl:0
  
     [Parsed_hwupload_0 @ 0x560df58f0ec0] auto-inserting filter
  
     'auto_scaler_0' between the filter 'graph 0 input from stream 0:0' and
  
     the filter 'Parsed_hwupload_0'
  Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
  

  • [DH] libavutil/hwcontext_vaapi.c

• Python, ffmpeg split list of audio files

  24 novembre 2020, par emil

  I know how to split one single audio file with python and ffmpeg :

  


  command = "ffmpeg -i a.wav -f segment -segment_time 60 -c copy out_dir/output%09d.wav"
command = shlex.split(command)
subprocess.run(command)


  


  For my current task, I have a list of several hundred .wav files I want to split.

  


  My current solution is :

  


  def parse_and_split_dir(directory, out_dir):
  files = [x for x in os.listdir(directory) if ".wav" in x]
  print(files)
  cntr = 0
  for wav in files:
    wav = wav.replace(" ", "\ ")
    temp_dir = os.path.join(out_dir, str(cntr))
    Path(temp_dir).mkdir(parents=True, exist_ok=True)
    temp_dir = os.path.join(temp_dir, "output%05d.wav")
    command = "ffmpeg -i {} -f segment -segment_time 60 -c copy {}".format(os.path.join(directory, wav), temp_dir)
    command = shlex.split(command)
    subprocess.run(command)
    cntr += 1




  


  I list all .wav files, and for each file I create a directory where I store the split files into. This implies that file naming start with index 1 for each new file.
E.g. folder 1 contains files ...1.wav to ...9.wav, folder 2 contains ...1.wav to ...13.wav and so on.

  


  In short, I ideally want to parse the whole directory with a single command, while keeping the naming continually from file to file, e.g. when the last wav saved its last split with ...10.split, the next split for the next file should be saved as ..11.split.

  


  I thought about first concatenating all the single files to one file, and then splitting them again (which introduces massive overhead), and unnecessarily consumes memory and disk space. An alternative I thought of was using a *.wav wildcard, but ffmpeg found no file called *.wav(which is expected).

  


  Related question : 1

  


• Master m3u8 file does not list streams

  23 septembre 2021, par kamoloff

  I have a video and I want to transcode it into hls using ffmpeg-python.
It works well with a video which has an audio stream.
But does not list stream playlists in master.m3u8 when I give a video file without audio as an input.

  


  problem : master.m3u8 is not listing stream, only contains :

  


  #EXTM3U
#EXT-X-VERSION:6


  


  expected :

  


  #EXTM3U
#EXT-X-VERSION:6
#EXT-X-STREAM-INF:BANDWIDTH=415800,RESOLUTION=1280x720,CODECS="avc1.64001f,mp4a.40.2"
prefix_stream_0.m3u8

#EXT-X-STREAM-INF:BANDWIDTH=105600,RESOLUTION=768x432,CODECS="avc1.64001e,mp4a.40.2"
prefix_stream_1.m3u8

#EXT-X-STREAM-INF:BANDWIDTH=105600,RESOLUTION=640x360,CODECS="avc1.64001e,mp4a.40.2"
prefix_stream_2.m3u8

#EXT-X-STREAM-INF:BANDWIDTH=52800,RESOLUTION=426x240,CODECS="avc1.640015,mp4a.40.2"
prefix_stream_3.m3u8