Remove compat with old FFmpeg codec params API

The new API has been introduced in 2016 in libavformat 57.xx, it's very
old.

This will avoid to maintain two code paths for codec parameters.

app/src/compat.h

@@ -11,16 +11,6 @@
 #include <libavformat/version.h>
 #include <SDL2/SDL_version.h>
 
-// In ffmpeg/doc/APIchanges:
-// 2016-04-11 - 6f69f7a / 9200514 - lavf 57.33.100 / 57.5.0 - avformat.h
-//   Add AVStream.codecpar, deprecate AVStream.codec.
-#if    (LIBAVFORMAT_VERSION_MICRO >= 100 /* FFmpeg */ && \
-        LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(57, 33, 100)) \
-    || (LIBAVFORMAT_VERSION_MICRO < 100 && /* Libav */ \
-        LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(57, 5, 0))
-# define SCRCPY_LAVF_HAS_NEW_CODEC_PARAMS_API
-#endif
-
 // In ffmpeg/doc/APIchanges:
 // 2018-02-06 - 0694d87024 - lavf 58.9.100 - avformat.h
 //   Deprecate use of av_register_input_format(), av_register_output_format(),

app/src/recorder.c

@@ -141,19 +141,11 @@ recorder_open(struct recorder *recorder, const AVCodec *input_codec) {
         return false;
     }
 
-#ifdef SCRCPY_LAVF_HAS_NEW_CODEC_PARAMS_API
     ostream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     ostream->codecpar->codec_id = input_codec->id;
     ostream->codecpar->format = AV_PIX_FMT_YUV420P;
     ostream->codecpar->width = recorder->declared_frame_size.width;
     ostream->codecpar->height = recorder->declared_frame_size.height;
-#else
-    ostream->codec->codec_type = AVMEDIA_TYPE_VIDEO;
-    ostream->codec->codec_id = input_codec->id;
-    ostream->codec->pix_fmt = AV_PIX_FMT_YUV420P;
-    ostream->codec->width = recorder->declared_frame_size.width;
-    ostream->codec->height = recorder->declared_frame_size.height;
-#endif
 
     int ret = avio_open(&recorder->ctx->pb, recorder->filename,
                         AVIO_FLAG_WRITE);
@@ -188,13 +180,8 @@ recorder_write_header(struct recorder *recorder, const AVPacket *packet) {
     // copy the first packet to the extra data
     memcpy(extradata, packet->data, packet->size);
 
-#ifdef SCRCPY_LAVF_HAS_NEW_CODEC_PARAMS_API
     ostream->codecpar->extradata = extradata;
     ostream->codecpar->extradata_size = packet->size;
-#else
-    ostream->codec->extradata = extradata;
-    ostream->codec->extradata_size = packet->size;
-#endif
 
     int ret = avformat_write_header(recorder->ctx, NULL);
     if (ret < 0) {