+int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header);
+
+/* useful helper to get mpeg audio stream infos. Return -1 if error in
+ header, otherwise the coded frame size in bytes */
+int avpriv_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
+
+/* fast header check for resync */
+static inline int ff_mpa_check_header(uint32_t header){
+ /* header */
+ if ((header & 0xffe00000) != 0xffe00000)
+ return -1;
+ /* layer check */
+ if ((header & (3<<17)) == 0)
+ return -1;
+ /* bit rate */
+ if ((header & (0xf<<12)) == 0xf<<12)
+ return -1;
+ /* frequency */
+ if ((header & (3<<10)) == 3<<10)
+ return -1;
+ return 0;
+}