libavcodec: Apply parameter change side data when decoding audio

Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/utils.c

@@ -40,6 +40,7 @@
 #include "thread.h"
 #include "audioconvert.h"
 #include "internal.h"
+#include "bytestream.h"
 #include <stdlib.h>
 #include <stdarg.h>
 #include <limits.h>
@@ -914,6 +915,47 @@ int attribute_align_arg avcodec_decode_audio3(AVCodecContext *avctx, int16_t *sa
 }
 #endif
 
+static void apply_param_change(AVCodecContext *avctx, AVPacket *avpkt)
+{
+    int size = 0;
+    const uint8_t *data;
+    uint32_t flags;
+
+    if (!(avctx->codec->capabilities & CODEC_CAP_PARAM_CHANGE))
+        return;
+
+    data = av_packet_get_side_data(avpkt, AV_PKT_DATA_PARAM_CHANGE, &size);
+    if (!data || size < 4)
+        return;
+    flags = bytestream_get_le32(&data);
+    size -= 4;
+    if (size < 4) /* Required for any of the changes */
+        return;
+    if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT) {
+        avctx->channels = bytestream_get_le32(&data);
+        size -= 4;
+    }
+    if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT) {
+        if (size < 8)
+            return;
+        avctx->channel_layout = bytestream_get_le64(&data);
+        size -= 8;
+    }
+    if (size < 4)
+        return;
+    if (flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE) {
+        avctx->sample_rate = bytestream_get_le32(&data);
+        size -= 4;
+    }
+    if (flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS) {
+        if (size < 8)
+            return;
+        avctx->width  = bytestream_get_le32(&data);
+        avctx->height = bytestream_get_le32(&data);
+        size -= 8;
+    }
+}
+
 int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
                                               AVFrame *frame,
                                               int *got_frame_ptr,
@@ -930,6 +972,8 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
         return AVERROR(EINVAL);
     }
 
+    apply_param_change(avctx, avpkt);
+
     if ((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size) {
         ret = avctx->codec->decode(avctx, frame, got_frame_ptr, avpkt);
         if (ret >= 0 && *got_frame_ptr) {