Ffmpeg, video to png

I have ffmpeg version 3.4.6 and it seems I have the same supported formats.

Here is the output of the command ffmpeg -formats | grep png:

ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)

  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
 DE apng            Animated Portable Network Graphics
 D  png_pipe        piped png sequence

Thanks, so it seems it’s not only Mac

I think you just need to provide a few more arguments to your ffmpeg command and that by default, ffmpeg assumes you want to convert the video to another video format.
I am running MacOS and ffmpeg 4.2.2 as well and am able to create a thumbnail with the following command:
ffmpeg -i sample.mp4 -ss 00:00:01.000 -vframes 1 output.png
Note we tell ffmpeg to take 1 frame (with -vframes 1), from a specific point (-ss <timestamp>) in the video.

Thanks for your response, I have to say I could generate png on the console, with this…

ffmpeg -ss 00:01 -i small.mp4 -t 00:02 -frames:v 1 outsmall.png

But it fails in the waffle transformation function

  def transform(:thumb, _) do
    {:ffmpeg, fn(input, output) -> "-ss 00:01 -i #{input} -t 00:02 -frames:v 1 #{output}" end, :png}
  end

[error] {:error, ["ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers\n  built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)\n  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.2_1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.0.1.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.0.1.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack\n  libavutil      56. 31.100 / 56. 31.100\n  libavcodec     58. 54.100 / 58. 54.100\n  libavformat    58. 29.100 / 58. 29.100\n  libavdevice    58.  8.100 / 58.  8.100\n  libavfilter     7. 57.100 /  7. 57.100\n  libavresample   4.  0.  0 /  4.  0.  0\n  libswscale      5.  5.100 /  5.  5.100\n  libswresample   3.  5.100 /  3.  5.100\n  libpostproc    55.  5.100 / 55.  5.100\nInput #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/folders/39/633s5xh54jjgntzl838zv56c0000gn/T//plug-1580/multipart-1580813808-273373503129595-7':\n  Metadata:\n    major_brand     : mp42\n    minor_version   : 0\n    compatible_brands: mp42isomavc1\n    creation_time   : 2010-03-20T21:29:11.000000Z\n    encoder         : HandBrake 0.9.4 2009112300\n  Duration: 00:00:05.57, start: 0.000000, bitrate: 551 kb/s\n    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(tv, bt709), 560x320, 465 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)\n    Metadata:\n      creation_time   : 2010-03-20T21:29:11.000000Z\n      encoder         : JVT/AVC Coding\n    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 83 kb/s (default)\n    Metadata:\n      creation_time   : 2010-03-20T21:29:11.000000Z\n[NULL @ 0x7fc22d802200] Unable to find a suitable output format for '/var/folders/39/633s5xh54jjgntzl838zv56c0000gn/T/ZE7BC755M55YFI2KSQF2BYJKNNFZOEPJ'\n/var/folders/39/633s5xh54jjgntzl838zv56c0000gn/T/ZE7BC755M55YFI2KSQF2BYJKNNFZOEPJ: Invalid argument\n"]}

I suppose the :png option of waffle trigger -f png

This one work, for animated png.

  def transform(:thumb, _) do
    {:ffmpeg, fn(input, output) -> "-i #{input} -f apng #{output}" end, :png}
  end

Are you sure that there are no spaces in input and output?

Thanks for your response,

I am quite confident with the syntax, as this is how it is written in the waffle documentation.

I thought png and jpg would be supported out of the box, but it seems not

It’s not a syntax issue they were speaking of but rather that the list form should be used as it will properly escape arguments where the string form will not.

However, running ffmpeg -ss 01:23:45 -i some-big-video-I-have.mpeg -vframes 1 -q:v 2 output.png works fine here and I have the same output from ffmpeg -formats | grep png as you do.

Thanks for your response, using this syntax is working for me at the command line, but not with waffle.

I still receive unable to find a suitable format when waffle tries to extract the image from the video.

Have you tried the list form in waffle though? I.E. instead of something like:

"some arguments and #{input} and #{output}"

Have you tried:

["some", "arguments", "and", input, "and", output]

Instead?

Oh nice, I will try and report.