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• как сделать 8 d музыку -> ffmpeg [closed]

  3 janvier 2023, par имя фамилия

  Всех приветствую, подскажите как через ffmpeg создать трек 8D
8D музыка это - метод постобработки аудиозаписи, когда диджеи берут уже существующий трек и микшируют его, создавая эффект движения звука вокруг слушателя.
По сути, 8D-аудио эмулирует звучание surround-формата Ambisonics. Последний подразумевает, что слушатель находится в центре «акустической сферы», по краям которой расставлены источники звука. (на одном форуме спросил что такое 8D)

  


  Писал на форуме, там не знаю решения, пробовал найти в открытых источниках, но видимо таким вопросом не задавались

  


• Using batch, how would you iterate through an array that you don't know how many values it may contain to run a function on each individual variable

  10 mai 2017, par Jay1995

  I have a batch file creating an array of variables it gets from a textfile, as follows :

  for /f "skip=1 tokens=9 delims= " %%a in (%findfile%) do set "_%%a=yes"
  
  set count = 0
  
  for /f "tokens=1* delims==#" %%b in ('set _') do (
  
      set /a count+=1
  
      set x=%%b
  
      set location[!count!]=!x:~1!
  
  )
  
  set %location%

  I’m trying to get each variable from the array to be looped into a function individually, but have no idea how to do it !!

  The location array storing all the variables has to be called into a for loop and the function I’m trying to get it to loop into is an FFMPEG function :

  for %%i in (%location%\*.mp4) do (if not exist "%%~ni\" MD "%%~ni"
  
  
  
      ffmpeg -i "%%i" -vframes 1 -f image2 -start_number 0 
  
      "%%~ni\%%~ni_Summary_%%3d.jpeg"
  
  
  
  )

  All HELP would be greatly appreciated

• Minimal sample of muxing two streams with no reencoding (av_interleaved_write_frame fails)

  19 juillet 2022, par Alvein

  What I'm trying to do : having two files, one is video-only and the other is audio-only, with identical durations, I want to "join" them in a single container.

  


  I previously made a routine which just copied all the streams inside a container to another one. No reencoding, etc. This works perfectly :

  


  while(true) {
    pkIn=av_packet_alloc();
    if(NULL==pkIn) {
        fprintf(stderr,"av_packet_alloc() failed");
        break;
    }
    iError=av_read_frame(fcIn,pkIn);
    if(0>iError)
        if(AVERROR_EOF==iError)
            break;
        else {
            fprintf(stderr,"av_read_frame() failed");
            break;
        }
    stIn=fcIn->streams[pkIn->stream_index];
    stOut=fcOut->streams[pkIn->stream_index];
    log_packet(fcIn,pkIn,"in");
    av_packet_rescale_ts(pkIn,stIn->time_base,stOut->time_base);
    pkIn->pos=-1;
    log_packet(fcOut,pkIn,"out");
    iError=av_interleaved_write_frame(fcOut,pkIn);
    if(0>iError) {
        fprintf(stderr,"av_interleaved_write_frame() failed");
        break;
    }
    av_packet_free(&pkIn);
}


  


  I just did the analogy and tried to do the same, but taking each stream from a distinct container, like this :

  


  while(true) {
    if(!bVideoInEOF) {
        pkVideoIn=av_packet_alloc();
        if(NULL==pkVideoIn) {
            fprintf(stderr,"av_packet_alloc(video in) failed");
            break;
        }
        iError=av_read_frame(fcVideoIn,pkVideoIn);
        if(0>iError)
            if(AVERROR_EOF==iError)
                bVideoInEOF=true;
            else {
                fprintf(stderr,"av_read_frame(video in) failed");
                break;
            }
        if(!bVideoInEOF) {
            log_packet(fcVideoIn,pkVideoIn,"video in");
            av_packet_rescale_ts(pkVideoIn,stVideoIn->time_base,stVideoOut->time_base);
            pkVideoIn->pos=-1;
            pkVideoIn->stream_index=stVideoOut->index; // Edit (2022-07-19)
            log_packet(fcVideoIn,pkVideoIn,"video out");
            iError=av_interleaved_write_frame(fcOut,pkVideoIn);
            if(0>iError) {
                fprintf(stderr,"av_interleaved_write_frame(video out) failed");
                break;
            }
        }
        av_packet_free(&pkVideoIn);
    }
    if(!bAudioInEOF) {
        pkAudioIn=av_packet_alloc();
        if(NULL==pkAudioIn) {
            fprintf(stderr,"av_packet_alloc(audio in) failed");
            break;
        }
        iError=av_read_frame(fcAudioIn,pkAudioIn);
        if(0>iError)
            if(AVERROR_EOF==iError)
                bAudioInEOF=true;
            else {
                fprintf(stderr,"av_read_frame(audio in) failed");
                break;
            }
        if(!bAudioInEOF) {
            log_packet(fcAudioIn,pkAudioIn,"audio in");
            av_packet_rescale_ts(pkAudioIn,stAudioIn->time_base,stAudioOut->time_base);
            pkAudioIn->pos=-1;
            pkAudioIn->stream_index=stAudioOut->index; // Edit (2022-07-19)
            log_packet(fcAudioIn,pkAudioIn,"audio out");
            iError=av_interleaved_write_frame(fcOut,pkAudioIn);
            if(0>iError) {
                fprintf(stderr,"av_interleaved_write_frame(audio out) failed");
                break;
            }
        }
        av_packet_free(&pkAudioIn);
    }
    if(bVideoInEOF&&bAudioInEOF)
        break;
}


  


  I know the previous code looks like redundant but I wanted to leave both streams "processing" separated the way you understand my plans.

  


  Anyway, that code ends quickly with "av_interleaved_write_frame(audio out) failed".

  


  The error detail is "Invalid argument", and the debugger shows this :

  


  


  Application provided invalid, non monotonically increasing dts to
muxer in stream 0.

  


  


  If I disable any of the main blocks "if(!bVideoInEOF)" / "if(!bAudioInEOF)", the file is written successfully, with the obvious lack of the disabled stream.

  


  I'm new into using this library so probably I'm doing something really stupid, or missing something obvious.

  


  Suggestions ?

  


  Edit (2022-07-19) :

  


  By checking the logs, I noticed I was writing every frame to the stream #0. Hence, the horrible jumps in PTS/DTS.

  


  Code edited by adding the corresponding "...->stream_index=" before each call to av_interleaved_write_frame().

  


  ...

  


  Though it works, I still think my code is far from perfect. Comments are welcome.