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• avdevice/decklink_enc : use 64bit format string for BMD timebase instead of long long

  2 juillet 2023, par Marton Balint

  avdevice/decklink_enc : use 64bit format string for BMD timebase instead of long long
  BMDTimeValue is defined as LONGLONG on Windows, but int64_t on Linux/Mac.
  Fixes format string warnings :
  libavdevice/decklink_enc.cpp : In function ‘void construct_cc(AVFormatContext*, decklink_ctx*, AVPacket*, klvanc_line_set_s*)’ :
  
  libavdevice/decklink_enc.cpp:424:48 : warning : format ‘%lld’ expects argument of type ‘long long int’, but argument 4 has type ‘BMDTimeValue aka long int’ [-Wformat=]
  
                  ctx->bmd_tb_num, ctx->bmd_tb_den) ;
  
   ^
  
  libavdevice/decklink_enc.cpp:424:48 : warning : format ‘%lld’ expects argument of type ‘long long int’, but argument 5 has type ‘BMDTimeValue aka long int’ [-Wformat=]
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavdevice/decklink_enc.cpp

• FFmpeg video has an excessively long duration

  8 juillet 2023, par daraem

  When using ytdl-core and ffmpeg-static to download high quality youtube videos, the output video is supposedly thousands of hours long, which makes it not let me advance the video in a media player. The error only occurs in windows 10 players. In VLC or Discord it does not happen.

  


          res.header("Content-Disposition", `attachment;  filename=video.mp4`)

        let video = ytdl(link, {
            filter: 'videoonly'
        })
        let audio = ytdl(link, {
            filter: 'audioonly',
            highWaterMark: 1 << 25
        });
        const ffmpegProcess = cp.spawn(ffmpeg, [
            '-i', `pipe:3`,
            '-i', `pipe:4`,
            '-map', '1:0',
            '-map', '0:0',
            '-vcodec', 'libx264',
            '-c:v', 'libx264',
            '-c:a', 'aac',
            '-crf', '27',
            '-preset', 'veryslow',
            '-b:v', '1500k',
            '-b:a', '128k',
            '-movflags', 'frag_keyframe+empty_moov',
            '-f', 'mp4',
            '-loglevel', 'error',
            '-',
        ], {
            stdio: [
                'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
            ],
        });
    
        video.pipe(ffmpegProcess.stdio[3]);
        audio.pipe(ffmpegProcess.stdio[4]);
        ffmpegProcess.stdio[1].pipe(res);
    
        let ffmpegLogs = ''
    
        ffmpegProcess.stdio[2].on(
            'data',
            (chunk) => {
                ffmpegLogs += chunk.toString()
            }
        )
    
        ffmpegProcess.on(
            'exit',
            (exitCode) => {
                if (exitCode === 1) {
                    console.error(ffmpegLogs)
                }
            }
        )


  


  I've tried changing the codecs options. But I'm not sure what I'm doing

  


• ffmpeg does not recognize long string filter in execv

  4 mai 2023, par incertia

  I am writing some simple python script to call ffmpeg and concat some clips together. However, it doesn't work for reasons I am unable to explain.

  


  below is a working version of the code after some debugging

  


  inputs = sorted(list(askopenfilenames()))
n = len(inputs)

filter = []
for i in range(n):
    filter.append("[{}:v]".format(i))
    filter.append("[{}:a]".format(i))
filter.append("concat={}:v=1:a=1".format(n))
filter.append("[v]")
filter.append("[a]")
filter = " ".join(filter)

fargs = zip(itertools.repeat('-i'), inputs)
fargs = itertools.chain(
    ["ffmpeg"],
    itertools.chain.from_iterable(fargs),
    ["-filter_complex", '"{}"'.format(filter), "-vsync", "vfr", "-map", "[v]", "-map", "[a]"],
    ["-c:v", "libx264", "-crf", "{}".format(quality)],
    ["-c:a", "aac", "-b:a", "192k"],
    [out]
    )

os.execvp("ffmpeg", list(fargs))


  


  but the entire fargs construction causes ffmpeg to complain about the filter chain when quotes are not utilized. e.g. by utilizing the below process

  


  fargs = itertools.chain(
    ["ffmpeg", "-loglevel", "debug"],
    itertools.chain.from_iterable(fargs),
    #["-filter_complex", '"{}"'.format(filter), "-vsync", "vfr", "-map", "[v]", "-map", "[a]"],
    ["-filter_complex", filter, "-vsync", "vfr", "-map", "[v]", "-map", "[a]"],
    ["-c:v", "libx264", "-crf", "{}".format(quality)],
    ["-c:a", "aac", "-b:a", "192k"],
    [out]
    )


  


  we see that ffmpeg somehow sees this as multiple arguments

  


  Reading option '-filter_complex' ... matched as option 'filter_complex' (create a complex filtergraph) with argument '[0:v]'.
Reading option '[0:a]' ... matched as output url.
Reading option '[1:v]' ... matched as output url.
Reading option '[1:a]' ... matched as output url.
Reading option '[2:v]' ... matched as output url.
Reading option '[2:a]' ... matched as output url.
Reading option 'concat=3:v=1:a=1' ... matched as output url.
Reading option '[v]' ... matched as output url.
Reading option '[a]' ... matched as output url.


  


  even though a simple print(list(fargs)) yields

  


  ['ffmpeg', '-loglevel', 'debug', '-i', 'a.mp4', '-i', 'b.mp4', '-i', 'c.mp4', '-filter_complex', '[0:v] [0:a] [1:v] [1:a] [2:v] [2:a] concat=3:v=1:a=1 [v] [a]', '-vsync', 'vfr', '-map', '[v]', '-map', '[a]', '-c:v', 'libx264', '-crf', '20', '-c:a', 'aac', '-b:a', '192k', 'asdf.mp4']


  


  implying that the long filter string is being passed to ffmpeg as a single argument.