+
+int avpriv_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bit_rate)
+{
+ MPADecodeHeader s1, *s = &s1;
+
+ if (ff_mpa_check_header(head) != 0)
+ return -1;
+
+ if (avpriv_mpegaudio_decode_header(s, head) != 0) {
+ return -1;
+ }
+
+ switch(s->layer) {
+ case 1:
+ avctx->codec_id = CODEC_ID_MP1;
+ *frame_size = 384;
+ break;
+ case 2:
+ avctx->codec_id = CODEC_ID_MP2;
+ *frame_size = 1152;
+ break;
+ default:
+ case 3:
+ avctx->codec_id = CODEC_ID_MP3;
+ if (s->lsf)
+ *frame_size = 576;
+ else
+ *frame_size = 1152;
+ break;
+ }
+
+ *sample_rate = s->sample_rate;
+ *channels = s->nb_channels;
+ *bit_rate = s->bit_rate;
+ return s->frame_size;
+}