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• avformat_open_input fails intermittently with avfoundation due to "audio format is not supported"

  27 septembre 2019, par NaderNader

  My application uses the ffmpeg APIs (avformat, avdevice, etc) to open a selected audio input for encoding. For some inputs I can reliably open them the first time, but when I close and reopen that input later, the avformat_open_input() call fails due to "audio format is not supported". My testing shows that it never fails the first time after starting my, and has only about a 50% chance of success when reopening.

  The failure only occurs with my "Built-in Microphone" audio input. I have a USB audio card that reliably opens and closes repeatedly. I have read the documentation and see that the proper way to free the resources after opening is to call avformat_close_input. The only way I have found to guarantee success is to only open the input once.

  I have written a test program to recreate these failures.

  int main() {
  
  
  
      avdevice_register_all();
  
  
  
      cout << "Running open audio test" << endl;
  
  
  
  
  
      int i;
  
      for(i = 0; i< 10; i++) {
  
  
  
          AVDictionary* options = NULL;
  
          AVInputFormat* inputFormat = av_find_input_format("avfoundation");
  
          if (!inputFormat) {
  
              cout << "avfoundation inputFormat=null" << endl;
  
          }
  
  
  
          AVFormatContext* formatContext = avformat_alloc_context();
  
          int result = avformat_open_input(&formatContext, ":1", inputFormat, &options);
  
          if (result < 0) {
  
              char error[256];
  
              av_strerror(result, error, sizeof(error));
  
              cout << "result=" << result << " " << error << endl;
  
          } else {
  
              cout << "input opened successfully" << endl;
  
          }
  
  
  
          sleep(1);
  
  
  
          avformat_close_input(&formatContext);
  
  
  
          sleep(1);
  
  
  
      }
  
  
  
      return 0;
  
  }

  I would expect the main loop to succeed each time but a typical output shows a high failure rate :

  Running open audio test

  input opened successfully
  
  [avfoundation @ 0x7fdeb281de00] audio format is not supported
  
  result=-5 Input/output error
  
  [avfoundation @ 0x7fdeb2001400] audio format is not supported
  
  result=-5 Input/output error
  
  [avfoundation @ 0x7fdeb2001400] audio format is not supported
  
  result=-5 Input/output error
  
  input opened successfully
  
  input opened successfully
  
  input opened successfully
  
  [avfoundation @ 0x7fdeb2068800] audio format is not supported
  
  result=-5 Input/output error
  
  input opened successfully
  
  input opened successfully

  I have tried increasing the sleep time between close and open to 5 seconds, but saw no difference in behavior.

  The source of the failure is https://github.com/FFmpeg/FFmpeg/blob/master/libavdevice/avfoundation.m#L672

  It appears avfoundation.m internally is opening an input stream and grabbing an audio frame to determine the format, but the value returned is not valid sometimes, when the process has previously opened and closed that input.

  Am I not closing the resources properly ? Do I have a hardware issue specific to my macbook ?

  Additional Details :

  Tested MacBook Pro with MacOS Mojave 10.14.6
  Tested with Ffmpeg 3.4.1, 4.0, and 4.1

  list_devices :

  [AVFoundation input device @ 0x7f80fff066c0] AVFoundation video devices:
  
  [AVFoundation input device @ 0x7f80fff066c0] [0] FaceTime HD Camera
  
  [AVFoundation input device @ 0x7f80fff066c0] [1] Capture screen 0
  
  [AVFoundation input device @ 0x7f80fff066c0] AVFoundation audio devices:
  
  [AVFoundation input device @ 0x7f80fff066c0] [0] Behringer Duplex
  
  [AVFoundation input device @ 0x7f80fff066c0] [1] Built-in Microphone
  
  [AVFoundation input device @ 0x7f80fff066c0] [2] USB Audio CODEC

• FFMPEG : Adding font to Video gives error

  7 juin 2016, par janki gadhiya

  I am trying to execute ffmpeg on android. I have successfully executed 2-3 commands also. But i am stuck at one point where i am adding text to the video.

  Here is the command i am executing.

  NOT WORKING : because the text argument has a space between two words.

  "-i "+path+"out.mp4 -vf drawtext=fontfile="+path+"f1.ttf:text='Stack OverFlow' -y -c:v libx264 -c:a copy -movflags +faststart "+path+"output.mp4"

  WORKING : just removed space.

  "-i "+path+"out.mp4 -vf drawtext=fontfile="+path+"f1.ttf:text='StackOverFlow' -y -c:v libx264 -c:a copy -movflags +faststart "+path+"output.mp4"

  Here path contains my external Sd card’s path. out.mp4 and f1.ttf exists in my folder.

  My Question is why it is not working with space.

  Here is the stack trace i am getting.

  FAILED with output : WARNING: linker: /data/data/com.github.hiteshsondhi88.sampleffmpeg/files/ffmpeg has text relocations. This is wasting memory and prevents security hardening. Please fix.
  
  ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers
  
  built with gcc 4.8 (GCC)
  
  configuration: --target-os=linux --cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/i686-linux-android- --arch=x86 --cpu=i686 --enable-runtime-cpudetect --sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-fontconfig --enable-pthreads --disable-debug --disable-ffserver --enable-version3 --enable-hardcoded-tables --disable-ffplay --disable-ffprobe --enable-gpl --enable-yasm --disable-doc --disable-shared --enable-static --pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/vagrant/SourceCode/ffmpeg-android/build/x86 --extra-cflags='-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all -march=i686' --extra-ldflags='-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib -Wl,-z,relro -Wl,-z,now -pie' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=
  
  libavutil      55. 17.103 / 55. 17.103
  
  libavcodec     57. 24.102 / 57. 24.102
  
  libavformat    57. 25.100 / 57. 25.100
  
  libavdevice    57.  0.101 / 57.  0.101
  
  libavfilter     6. 31.100 /  6. 31.100
  
  libswscale      4.  0.100 /  4.  0.100
  
  libswresample   2.  0.101 /  2.  0.101
  
  libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/storage/emulated/0/Testing/out.mp4':
  
  Metadata:
  
  major_brand     : isom
  
  minor_version   : 512
  
  compatible_brands: isomiso2avc1mp41
  
  encoder         : Lavf57.25.100
  
  Duration: 00:00:05.00, start: 0.000000, bitrate: 117 kb/s
  
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 300x300 [SAR 40:33 DAR 40:33], 113 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
  Metadata:
  
  handler_name    : VideoHandler
  
  [NULL @ 0xb585f000] Unable to find a suitable output format for 'text='Stack'
  
  text='Stack: Invalid argument

  Why it is saying invalid argument. It will be great if any ffmpeg expert can guide me in what i am doing wrong here.

  I have refered this Question of SO : Text on video ffmpeg

• Mac terminal command to list files and sort by date to use in ffmpeg

  22 septembre 2020, par Jeff

  I am using a gopro to film a bunch of videos. I want to then take those videos directly from the SD card folder and concatenate them into a single video (bypass an editor) by using FFMPEG.

  


  I'm currently able to stitch together "chaptered" videos with the following example command on my Mac (10.13) :

  


  ffmpeg -f concat -safe 0 -i <(for f in /sdcardfolder/100GOPRO/GH*488.MP4; do echo "file '$f'"; done) -c copy /folder/video.mp4

  


  The reason for this is that the ffmpeg command requires a text file that looks like this :

  


  


  file '/folder/GH016992.MP4'

  
file '/folder/GH036990.MP4'

  
...

  


  


  The real command is this, which generates the list of files in the right format with file in front of each one and can be embedded into the ffmpeg command :

  


  for f in /Volumes/GoPro8/DCIM/100GOPRO/GH0*71*.MP4; do echo "file '$f'"; done

  


  I want to add 2 changes to this :

  


  


  1. List the files in date order (ascending) : I want the list of files to be in date order. But I can't figure out how to add a -sort or something to the for f in command.

     


  


  2. Allow a more robust set of file matching/filtering : Right now I can add basic regex like GH*488.MP4 or, with chapters which increments the first number, something like GH0[123]488.MP4 would work to just get the first few. But when I change it to be more flexible like GH0[0-9]71[0-9][0-9].MP4 - which would be necessary to match all files that were recorded yesterday, but nothing before then, the command doesn't like this regex. It seems to only accept a *.

     


  


  


  I looked at a few examples like https://opensource.com/article/19/6/how-write-loop-bash but there wasn't much more than just listing files.

  


  This boils down to a terminal command and isn't really related to FFMPEG but I hope it's helpful context.

  


  I imagined it would be something like this, but this definitely doesn't work :

  


  for f in (find /Volumes/GoPro8/DCIM/100GOPRO/GH0[0-9]71[0-9][0-9].MP4 -type f | sort); do echo "file '$f'"; done

  


  I'd appreciate any help ! Thanks !

  


  Update

  


  It looks like sorting isn't easy with Mac tools so I gave up and wrote a much simpler Ruby script that could execute everything for me. This is not really an answer to my question above but it is a solution.

  


  Here I can easily write the text file necessary for ffmpeg and I can also filter files with a regex on the name, filter for a particular date, and size. Then, via the script, simply execute the ffmpeg command with args to concat files. I can also have it immediately resample the file to compress it (gopro videos are giant and I'm ok with a much lower bitrate if I want to save raw footage).

  


  I got lucky with this Dir.entries in Ruby - it seems to automatically sort by date ? I don't know how to sort it otherwise.

  


  PATH = '/Volumes/GoPro8/DCIM/100GOPRO/'
NEW_FILENAME = '/folder/new-file.mp4'
video_list = '/folder/ffmpeg-list.txt'

# create the text file
File.delete(video_list) if File.exist?(video_list)
i = 1
Dir.entries(PATH).each do |f|
    d = File.mtime(PATH + f)
    size = File.size(PATH + f)
    if f.match(/GH0.*.MP4/) && d.to_s.match(/2020-07-30/) && size.to_i < 1000000000
        puts "#{i}\t#{f}\t#{d}\t#{size}"
        File.write(video_list, "file #{PATH + f}\n", mode: "a")
        i= i+1
    end
end

command = "ffmpeg -f concat -safe 0 -i #{video_list} -c copy #{NEW_FILENAME}"

puts "executing concatenate..."
puts command
system(command)