ffmpeg 5 compatibility

[xiaoqiangwang]

On RHEL9 the ffmpeg package from rpmfusion has version 5.1.4. The build gives errors

../ffmpegServerApp/src/ffmpegCommon.cpp: In function ‘void ffmpegInitialise()’:
../ffmpegServerApp/src/ffmpegCommon.cpp:12:5: error: ‘avcodec_register_all’ was not declared in this scope
   12 |     avcodec_register_all();
      |     ^~~~~~~~~~~~~~~~~~~~
../ffmpegServerApp/src/ffmpegCommon.cpp:15:5: error: ‘av_register_all’ was not declared in this scope
   15 |     av_register_all();
      |     ^~~~~~~~~~~~~~~

According to https://github.com/FFmpeg/FFmpeg/blob/9fb6f024c3db2c19aca7f5f93c6843b7e5d1eecf/doc/APIchanges#L1131, these functions have been deprecated and removed later. After removing these two, there are further errors,

../ffmpegServerApp/src/ffmpegFile.cpp: In member function ‘virtual asynStatus ffmpegFile::openFile(const char*, NDFileOpenMode_t, NDArray*)’:
../ffmpegServerApp/src/ffmpegFile.cpp:50:15: error: invalid conversion from ‘const AVOutputFormat*’ to ‘AVOutputFormat*’ [-fpermissive]
   50 |     fmt = oc->oformat;
      |           ~~~~^~~~~~~
      |               |
      |               const AVOutputFormat*
../ffmpegServerApp/src/ffmpegFile.cpp:71:33: error: invalid conversion from ‘const AVCodec*’ to ‘AVCodec*’ [-fpermissive]
   71 |     codec = avcodec_find_encoder(codec_id);
      |             ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~
      |                                 |
      |                                 const AVCodec*
../ffmpegServerApp/src/ffmpegFile.cpp:88:23: error: ‘AVStream’ {aka ‘struct AVStream’} has no member named ‘codec’
   88 |         c = video_st->codec;
      |                       ^~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:97:9: error: ‘avcodec_get_context_defaults3’ was not declared in this scope
   97 |         avcodec_get_context_defaults3(c, codec);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:150:23: error: ‘AVStream’ {aka ‘struct AVStream’} has no member named ‘codec’
  150 |         c = video_st->codec;
      |                       ^~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:214:25: error: ‘AVPicture’ was not declared in this scope; did you mean ‘inPicture’?
  214 |         avpicture_fill((AVPicture *)scPicture,(uint8_t *)scArray->pData,c->pix_fmt,c->width,c->height);
      |                         ^~~~~~~~~
      |                         inPicture
../ffmpegServerApp/src/ffmpegFile.cpp:214:36: error: expected primary-expression before ‘)’ token
  214 |         avpicture_fill((AVPicture *)scPicture,(uint8_t *)scArray->pData,c->pix_fmt,c->width,c->height);
      |                                    ^
../ffmpegServerApp/src/ffmpegFile.cpp:214:9: error: ‘avpicture_fill’ was not declared in this scope
  214 |         avpicture_fill((AVPicture *)scPicture,(uint8_t *)scArray->pData,c->pix_fmt,c->width,c->height);
      |         ^~~~~~~~~~~~~~
../ffmpegServerApp/src/ffmpegFile.cpp: In member function ‘virtual asynStatus ffmpegFile::writeFile(NDArray*)’:
../ffmpegServerApp/src/ffmpegFile.cpp:251:19: warning: ‘void av_init_packet(AVPacket*)’ is deprecated [-Wdeprecated-declarations]
  251 |     av_init_packet(&pkt);
      |     ~~~~~~~~~~~~~~^~~~~~
In file included from /usr/include/ffmpeg/libavcodec/avcodec.h:45,
                 from ../ffmpegServerApp/src/ffmpegCommon.h:10,
                 from ../ffmpegServerApp/src/ffmpegFile.cpp:2:
/usr/include/ffmpeg/libavcodec/packet.h:512:6: note: declared here
  512 | void av_init_packet(AVPacket *pkt);
      |      ^~~~~~~~~~~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:255:11: error: ‘avcodec_encode_video2’ was not declared in this scope; did you mean ‘avcodec_encode_subtitle’?
  255 |     ret = avcodec_encode_video2(c, &pkt, this->scPicture, &got_output);
      |           ^~~~~~~~~~~~~~~~~~~~~
      |           avcodec_encode_subtitle
../ffmpegServerApp/src/ffmpegFile.cpp:263:16: error: ‘AVCodecContext’ {aka ‘struct AVCodecContext’} has no member named ‘coded_frame’
  263 |         if (c->coded_frame->key_frame)
      |                ^~~~~~~~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:274:49: error: ‘AVStream’ {aka ‘struct AVStream’} has no member named ‘codec’
  274 |     scPicture->pts += av_rescale_q(1, video_st->codec->time_base, video_st->time_base);
      |                                                 ^~~~~
../ffmpegServerApp/src/ffmpegFile.cpp: In member function ‘virtual asynStatus ffmpegFile::closeFile()’:
../ffmpegServerApp/src/ffmpegFile.cpp:312:37: error: ‘AVStream’ {aka ‘struct AVStream’} has no member named ‘codec’
  312 |             avcodec_close(video_st->codec);
      |                                     ^~~~~
../ffmpegServerApp/src/ffmpegFile.cpp:317:35: error: ‘AVStream’ {aka ‘struct AVStream’} has no member named ‘codec’
  317 |         av_freep(&oc->streams[i]->codec);
      |                                   ^~~~~

It seems these functions are deprecated since ffmpeg 4 and now removed in ffmpeg 5.