Fix FFmpeg 5.x compatibility issues

[fergarciadlc]

Fix FFmpeg 5.x+ compatibility issues

Problem

Essentia fails to build/import on systems with FFmpeg 5.x+ due to deprecated and removed APIs, causing undefined symbol: avcodec_decode_audio4 errors.

Solution

Updated AudioLoader and AudioContext to use modern FFmpeg APIs:

• Replace avcodec_decode_audio4() with avcodec_send_packet() + avcodec_receive_frame()
• Replace avcodec_encode_audio2() with avcodec_send_frame() + avcodec_receive_packet()
• Remove deprecated av_register_all() calls
• Update AVStream->codec to AVStream->codecpar
• Replace AVCodecContext->channels with AVCodecContext->ch_layout
• Fix flushPacket() to properly handle AVERROR_EOF

Testing

• Builds successfully with FFmpeg 7.1.1
• All audio formats (WAV, MP3, FLAC) load without warnings
• No runtime errors or compatibility issues

Closes

• Fixes Support ffmpeg version 5 #1248
• Related to macOS Catalina MonoWriter: Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead #1154

How to Test

Tested with python 3.8.13 (numpy==1.24) and python 3.9 (numpy==2.0.2)
ffmpeg version 7.1.1

After installing numpy, six and pyyaml

# Build with waf
python waf configure --with-python
python waf build -j4
python waf install

Then tested audio loading functionality:

import essentia.standard

# Test with different audio formats
loader = essentia.standard.AudioLoader(filename='path/to/your/audio.wav')
audio, sr, nc, md5, br, codec = loader()
print(f'Loaded: {sr}Hz, {nc} channels, codec: {codec}')

Should work without warnings on systems with FFmpeg 5.x+.

[xaviliz]

Hi @fergarciadlc, thanks a lot for your fix and solutions. Please, could you provide the building command for ffmpeg-7.1.1 so I can test your changes asap? Thanks in advance.

[fergarciadlc]

@xaviliz upgraded using last available Homebrew version; But releases can be found in the official ffmpeg releases section
https://www.ffmpeg.org/download.html#releases

[xaviliz]

Yes, I am trying to compile from the release. It is nice to update the building command then the python wheels can be also updated. No problem, I will check it with homebrew and Linux as well.

[xaviliz]

There are issues with 10-second impulses.

>>> from essentia.standard import AudioLoader
>>> audio, sr, ch, md5, _, _ = AudioLoader(filename="test/audio/generated/synthesised/impulse/flac/impulses_1second_44100.flac")()
>>> print(len(audio), sr, ch)
537000 44100.0 1

Did you checked the audio length in your tests?

[xaviliz]

The same issues when installing FFmpeg from homebrew. In fact, it’s likely doesn’t fully support 24/32-bit WAV decoding. It looks like it should be compiled from the source code.

[xaviliz]

There are still issues running the unittests:

1. The audio length is incorrect.
2. All writers and loaders fail in most of tests.

It still needs some work in the AudioLoader and AudioContext classes.