Add more consts

Some decoder and recorder functions must not write to AVCodec and
AVPacket.

app/src/decoder.c

@@ -39,7 +39,7 @@ decoder_init(struct decoder *decoder, struct video_buffer *vb) {
 }
 
 bool
-decoder_open(struct decoder *decoder, AVCodec *codec) {
+decoder_open(struct decoder *decoder, const AVCodec *codec) {
     decoder->codec_ctx = avcodec_alloc_context3(codec);
     if (!decoder->codec_ctx) {
         LOGC("Could not allocate decoder context");
@@ -62,7 +62,7 @@ decoder_close(struct decoder *decoder) {
 }
 
 bool
-decoder_push(struct decoder *decoder, AVPacket *packet) {
+decoder_push(struct decoder *decoder, const AVPacket *packet) {
 // the new decoding/encoding API has been introduced by:
 // <http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=7fc329e2dd6226dfecaa4a1d7adf353bf2773726>
 #ifdef SCRCPY_LAVF_HAS_NEW_ENCODING_DECODING_API

app/src/decoder.h

@@ -15,13 +15,13 @@ void
 decoder_init(struct decoder *decoder, struct video_buffer *vb);
 
 bool
-decoder_open(struct decoder *decoder, AVCodec *codec);
+decoder_open(struct decoder *decoder, const AVCodec *codec);
 
 void
 decoder_close(struct decoder *decoder);
 
 bool
-decoder_push(struct decoder *decoder, AVPacket *packet);
+decoder_push(struct decoder *decoder, const AVPacket *packet);
 
 void
 decoder_interrupt(struct decoder *decoder);

app/src/recorder.c

@@ -59,7 +59,7 @@ recorder_get_format_name(enum recorder_format format) {
 }
 
 bool
-recorder_open(struct recorder *recorder, AVCodec *input_codec) {
+recorder_open(struct recorder *recorder, const AVCodec *input_codec) {
     const char *format_name = recorder_get_format_name(recorder->format);
     SDL_assert(format_name);
     const AVOutputFormat *format = find_muxer(format_name);
@@ -128,7 +128,7 @@ recorder_close(struct recorder *recorder) {
 }
 
 static bool
-recorder_write_header(struct recorder *recorder, AVPacket *packet) {
+recorder_write_header(struct recorder *recorder, const AVPacket *packet) {
     AVStream *ostream = recorder->ctx->streams[0];
 
     uint8_t *extradata = av_malloc(packet->size * sizeof(uint8_t));

app/src/recorder.h

@@ -27,7 +27,7 @@ void
 recorder_destroy(struct recorder *recorder);
 
 bool
-recorder_open(struct recorder *recorder, AVCodec *input_codec);
+recorder_open(struct recorder *recorder, const AVCodec *input_codec);
 
 void
 recorder_close(struct recorder *recorder);