update libav API or switch to FFMPEG

[Be-ing]

Hi, we are thinking of replacing the Queen Mary DSP key analyzer in Mixxx with libKeyFinder. I wanted to give this application a try before we work on that.

I am trying to build is_KeyFinder on Fedora 31 but cannot because it depends on some old version of libav. There are not Fedora packages for libav anymore; RPMFusion only packages FFMPEG. So I downloaded the latest libav (12) from https://libav.org/download/ . I had to add #include <libavresample/avresample.h> to source/decoderlibav.h then find-and-replace ReSampleContext with AVAudioResampleContext. But there are still dependencies on outdated libav APIs.

I think the best way forward would be moving to FFMPEG. At the least you could document which old version of libav is required to build this.

source/decoderlibav.cpp:26:122: error: use of undeclared identifier 'AVCODEC_MAX_AUDIO_FRAME_SIZE'
AudioFileDecoder::AudioFileDecoder(const QString& filePath, const int maxDuration) : filePathCh(NULL), frameBufferSize(((AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2) * sizeof(uint8_t)), audioStream(-1), badPacketCount(0), badPacketThreshold(100), codec(NULL), fCtx(NULL), cCtx(NULL), dict(NULL), rsCtx(NULL) {
                                                                                                                         ^
source/decoderlibav.cpp:56:27: warning: 'codec' is deprecated [-Wdeprecated-declarations]
    if (fCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
                          ^
/usr/include/libavformat/avformat.h:711:5: note: 'codec' has been explicitly marked deprecated here
    attribute_deprecated
    ^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:79:38: warning: 'codec' is deprecated [-Wdeprecated-declarations]
  cCtx = fCtx->streams[audioStream]->codec;
                                     ^
/usr/include/libavformat/avformat.h:711:5: note: 'codec' has been explicitly marked deprecated here
    attribute_deprecated
    ^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:95:11: error: use of undeclared identifier 'av_audio_resample_init'
  rsCtx = av_audio_resample_init(cCtx->channels, cCtx->channels, cCtx->sample_rate, cCtx->sample_rate, AV_SAMPLE_FMT_S16, cCtx->sample_fmt, 0, 0, 0, 0);
          ^
source/decoderlibav.cpp:108:22: error: use of undeclared identifier 'audio_resample_close'; did you mean 'avresample_close'?
  if (rsCtx != NULL) audio_resample_close(rsCtx);
                     ^~~~~~~~~~~~~~~~~~~~
                     avresample_close
/usr/include/libavresample/avresample.h:204:6: note: 'avresample_close' declared here
void avresample_close(AVAudioResampleContext *avr);
     ^
source/decoderlibav.cpp:115:21: error: use of undeclared identifier 'av_close_input_file'
  if (fCtx != NULL) av_close_input_file(fCtx);
                    ^
source/decoderlibav.cpp:132:44: warning: 'av_free_packet' is deprecated [-Wdeprecated-declarations]
    if (avpkt.stream_index != audioStream) av_free_packet(&avpkt);
                                           ^
/usr/include/libavcodec/avcodec.h:3907:1: note: 'av_free_packet' has been explicitly marked deprecated here
attribute_deprecated
^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:141:9: warning: 'av_free_packet' is deprecated [-Wdeprecated-declarations]
        av_free_packet(&avpkt);
        ^
/usr/include/libavcodec/avcodec.h:3907:1: note: 'av_free_packet' has been explicitly marked deprecated here
attribute_deprecated
^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:147:5: warning: 'av_free_packet' is deprecated [-Wdeprecated-declarations]
    av_free_packet(&avpkt);
    ^
/usr/include/libavcodec/avcodec.h:3907:1: note: 'av_free_packet' has been explicitly marked deprecated here
attribute_deprecated
^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:151:3: warning: 'av_free_packet' is deprecated [-Wdeprecated-declarations]
  av_free_packet(&avpkt);
  ^
/usr/include/libavcodec/avcodec.h:3907:1: note: 'av_free_packet' has been explicitly marked deprecated here
attribute_deprecated
^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:164:25: error: use of undeclared identifier 'avcodec_decode_audio3'; did you mean 'avcodec_decode_audio4'?
    int bytesConsumed = avcodec_decode_audio3(cCtx, dataBuffer, &dataSize, &tempPacket);
                        ^~~~~~~~~~~~~~~~~~~~~
                        avcodec_decode_audio4
/usr/include/libavcodec/avcodec.h:4151:5: note: 'avcodec_decode_audio4' declared here
int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame,
    ^
source/decoderlibav.cpp:164:53: error: cannot initialize a parameter of type 'AVFrame *' with an lvalue of type 'int16_t *' (aka 'short *')
    int bytesConsumed = avcodec_decode_audio3(cCtx, dataBuffer, &dataSize, &tempPacket);
                                                    ^~~~~~~~~~
/usr/include/libavcodec/avcodec.h:4151:59: note: passing argument to parameter 'frame' here
int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame,
                                                          ^
source/decoderlibav.cpp:164:25: warning: 'avcodec_decode_audio4' is deprecated [-Wdeprecated-declarations]
    int bytesConsumed = avcodec_decode_audio3(cCtx, dataBuffer, &dataSize, &tempPacket);
                        ^
/usr/include/libavcodec/avcodec.h:4150:1: note: 'avcodec_decode_audio4' has been explicitly marked deprecated here
attribute_deprecated
^
/usr/include/libavutil/attributes.h:76:49: note: expanded from macro 'attribute_deprecated'
#    define attribute_deprecated __attribute__((deprecated))
                                                ^
source/decoderlibav.cpp:175:28: error: use of undeclared identifier 'audio_resample'
      int resampleResult = audio_resample(rsCtx, (short*)frameBufferConverted, (short*)frameBuffer, newSamplesDecoded);
                           ^
7 warnings and 7 errors generated.
make: *** [Makefile:1344: decoderlibav.o] Error 1
make: *** Waiting for unfinished jobs....

[Be-ing]

Adding libKeyFiinder to Mixxx's analyzers was easier than trying to getting this to build, so I personally don't have a use for this application anymore. Thanks for the library!

[twhitehead]

NixOS is in the process of dumping libav due to the fact that it is not being maintained and is accumulating a fairly extensive list of known vulnerabilities. For example

CVE-2014-5271 CVE-2015-3395 CVE-2015-5479 CVE-2016-3062 CVE-2016-6832 CVE-2016-7393 CVE-2016-7424 CVE-2016-8675 CVE-2016-8676 CVE-2017-16803 CVE-2017-9051 CVE-2018-11102 CVE-2018-11224 CVE-2018-18826 CVE-2018-18827 CVE-2018-18828 CVE-2018-18829 CVE-2018-19128 CVE-2018-19129 CVE-2018-19130 CVE-2018-20001 CVE-2018-5684 CVE-2018-5766 CVE-2019-14371 CVE-2019-14372 CVE-2019-14441 CVE-2019-14442 CVE-2019-14443 CVE-2019-9717 CVE-2019-9719 CVE-2019-9720

Would be nice if this could be ported to ffmpeg so we could continue to offer it to our users.

[Be-ing]

This application is unmaintained. If any NixOS users want to use KeyFinder, the easiest way would be using Mixxx 2.3 (currently in beta). We have forked the libkeyfinder library (with @ibsh's permission) and replaced QMake with CMake. You may also consider packaging keyfinder-cli.