Add support for decoding input with ffmpeg (Linux)

[WilliamTambellini]

WIP: for early review only. Do not merge.

• add cmake option to build with ffmpeg
• search for ffmpeg at cmake time
• include ffmpegs/libav headers in main.cpp Remaining todos:
• if needed convert input file to wav 16khz in main.cpp

[WilliamTambellini]

@ggerganov @slaren could you please early review before I move on ? Best, WT.

[ggerganov]

We can add the FindFFmpeg.cmake script in the cmake folder and use it to find ffmpeg libs

Probably the conversion functionality should be implemented in common.cpp so that it can be reused by all examples, not just main

[WilliamTambellini]

We can add the FindFFmpeg.cmake script in the cmake folder and use it to find ffmpeg libs

done

Probably the conversion functionality should be implemented in common.cpp so that it can be reused by all examples, not just main

ok

[WilliamTambellini]

@ggerganov reready for review, tks

[WilliamTambellini]

@petterreinholdtsen review please

[WilliamTambellini]

@arthw review please

[WilliamTambellini]

@ggerganov retouched. Reready for final review.

[ggerganov]

Hm, I think you didn't push the correct revision - I don't see any changes since last time

[WilliamTambellini]

oops indeed @ggerganov . Just pushed the latest retouches.

[WilliamTambellini]

tks @ggerganov Any way to do a new minor release soon (eg 1.6.1) ?

[ggerganov]

done

[data-man]

Unfortunately cannot be built with FFmpeg 7.0.

[clort81]

1b51fdf170714dcdd8fb9cfd02dcee684aac6150 is the first bad commit
commit 1b51fdf170714dcdd8fb9cfd02dcee684aac6150
Author: William Tambellini <wtambellini@sdl.com>
Date:   Tue May 21 08:31:41 2024 -0700

    examples : add support for decoding input with ffmpeg (Linux) (#2133)

/pr/Neural/Voice_Recognition_Whispr_GGML/good-whisper.cpp/examples/ffmpeg-transcode.cpp: In function ‘int decode_audio(audio_buffer*, s16**, int*)’:
/pr/Neural/Voice_Recognition_Whispr_GGML/good-whisper.cpp/examples/ffmpeg-transcode.cpp:207:5: error: ‘av_register_all’ was not declared in this scope
  207 |     av_register_all(); // from avformat. Still a must-have call for ffmpeg v3! (can be skipped for later versions)
      |     ^~~~~~~~~~~~~~~

ffmpeg                                        7:5.1.4-0+deb12u1 

devuan linux

[Displacer]

1b51fdf170714dcdd8fb9cfd02dcee684aac6150 is the first bad commit
commit 1b51fdf170714dcdd8fb9cfd02dcee684aac6150
Author: William Tambellini <wtambellini@sdl.com>
Date:   Tue May 21 08:31:41 2024 -0700

    examples : add support for decoding input with ffmpeg (Linux) (#2133)

/pr/Neural/Voice_Recognition_Whispr_GGML/good-whisper.cpp/examples/ffmpeg-transcode.cpp: In function ‘int decode_audio(audio_buffer*, s16**, int*)’:
/pr/Neural/Voice_Recognition_Whispr_GGML/good-whisper.cpp/examples/ffmpeg-transcode.cpp:207:5: error: ‘av_register_all’ was not declared in this scope
  207 |     av_register_all(); // from avformat. Still a must-have call for ffmpeg v3! (can be skipped for later versions)
      |     ^~~~~~~~~~~~~~~

ffmpeg                                        7:5.1.4-0+deb12u1 

devuan linux

can probably be fixed with:

if LIBAVFORMAT_VERSION_MAJOR < 56

av_register_all(); // from avformat. Still a must-have call for ffmpeg v3! (can be skipped for later versions)

endif

Change 56 to correct ffmpeg version. media-video/ffmpeg-4.4.4 seems to have 56 version (but i am not sure)