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• avfilter/buffersink : fix order of operation with = and

  2 novembre 2023, par Michael Niedermayer

  avfilter/buffersink : fix order of operation with = and <0
  Reviewed-by : Sean McGovern <gseanmcg@gmail.com>
  
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavfilter/buffersink.c

• ffmpeg concat work in one order but not the other

  11 octobre 2023, par user3083171

  So I took a video and cut it two ways, one with reencoding and one without reencoding, call them R and C (cut). Im trying to do concatenation without reencoding, and I'm able to concat the video in all orders , , , , but the sound disappears for and I have no idea why.

  


  I know I can concatenate with reencoding, but my question is specifically if someone knows why the sound drops in and maybe how to fix it. Here is some code in python

  


  import os
import json
import subprocess

video_file = 'yourpath/vid.mp4'
# get the time between frames

ffprobe_command = f"ffprobe -v error -select_streams v:0 -show_entries stream=width,height,r_frame_rate,duration,nb_frames,codec_name -of json {video_file}"
result = subprocess.run(ffprobe_command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)

# Parse the JSON output from ffprobe
json_data = json.loads(result.stdout)

# Extract video information from the JSON data
video_info = {
    'length': int(json_data['streams'][0]['nb_frames']),
    'frames': int(json_data['streams'][0]['nb_frames']),
    'duration_seconds': float(json_data['streams'][0]['duration']),
    'fps': eval(json_data['streams'][0]['r_frame_rate']),
    'codec': json_data['streams'][0]['codec_name'],
    'time_between_frames': 1 / eval(json_data['streams'][0]['r_frame_rate'])
}
# get the time between frames
delta = video_info['time_between_frames']

directory, filename_with_extension = os.path.split(video_file)
filename, extension = os.path.splitext(filename_with_extension)
tag = "_reencode"
new_filename = f"{filename}{tag}{extension}"
reencode_file = directory + "/" + new_filename

tag = "_justcut"
new_filename = f"{filename}{tag}{extension}"
justcut_file = directory + "/" + new_filename

tag = "_concat"
new_filename = f"{filename}{tag}{extension}"
concat_file = directory + "/" + new_filename

start_time = 0.0 + 108 * delta
end_time = start_time + 180 * delta
end_frame = round(end_time / delta)
start_frame = round(start_time / delta)

# Reencode
cmd = [
    "ffmpeg",
    "-i", video_file,
    "-ss", str(start_time),
    "-to", str(end_time),
    # "-c:a", "copy",
    "-c:v", "libx264",
    "-bf", str(0), # no B frames
    "-crf", str(18),  # new
    "-preset", "slow",  # new
    # "-g", str(60), #forces key_frames
    # "-force_key_frames expr:gte(t, n_forced * GOP_LEN_IN_SECONDS)"
    # "-c:v", "mpeg4", #"copy", #"mpeg4"
    # "-q:v", "2",
    "-c:a", "copy",
    # "video_track_timescale", str(90)+"K",
    reencode_file
]
subprocess.run(cmd, check=True)

# Just Cut
cmd = [
    'ffmpeg',
    '-i', video_file,
    '-c', 'copy',
    '-ss', str(start_time),
    '-to', str(end_time),
    justcut_file
]
subprocess.run(cmd, check=True)

# Concat without reencoding
def concatenate_videos_without_reencoding(video1, video2, output_file):
    try:
        # Create a text file listing the videos to concatenate
        with open('input.txt', 'w') as f:
            f.write(f"file '{video1}'\n")
            f.write(f"file '{video2}'\n")

        # Run ffmpeg command to concatenate videos without re-encoding
        # subprocess.run(['ffmpeg', '-f', 'concat', '-safe', '0', '-i', 'input.txt', '-c', 'copy', output_file])

        subprocess.run(
            ['ffmpeg', '-f', 'concat', '-safe', '0', '-i', 'input.txt', '-vcodec', 'copy',
             '-acodec', 'copy', "-strict", "experimental", output_file])

        print(f"Videos concatenated successfully without re-encoding. Output saved to {output_file}")
    except Exception as e:
        print(f"An error occurred: {e}")
    finally:
        # Remove the temporary input file
        if os.path.exists('input.txt'):
            os.remove('input.txt')
# Has sound
concatenate_videos_without_reencoding(justcut_file, justcut_file, concat_file)
os.remove(concat_file)
# Has sound
concatenate_videos_without_reencoding(reencode_file, reencode_file, concat_file)
os.remove(concat_file)
# Has sound
concatenate_videos_without_reencoding(justcut_file, reencode_file, concat_file)
os.remove(concat_file)
# Has NO sound
concatenate_videos_without_reencoding(reencode_file, justcut_file, concat_file)
os.remove(concat_file)


  


  As you can see I tried a bunch of stuff but I have no clue why the audio is not working. I've tried to force the two input videos to be as similar as possible in term of specs and keyframes and fps etc. Nothing seems to work, kinda frustrating.

  


  I've also tried this with both mpeg4 and h264 and different framerates, but still get this behavior.

  


• vulkan_hevc : use diagonal scan order for scaling lists

  28 juillet 2023, par Benjamin Cheng

  vulkan_hevc : use diagonal scan order for scaling lists
  The hevc parser parses the diagonal scan order in bitstream into raster
  
  scan order. However, the Vulkan spec wants it as specified in H265 spec,
  
  which is diagonal scan order.
  Tested on RADV.
  v2 : fix copy-paste typo with PPS.
  

  • [DH] libavcodec/vulkan_hevc.c