/*
* MPEG Audio header decoder
- * Copyright (c) 2001, 2002 Fabrice Bellard.
+ * Copyright (c) 2001, 2002 Fabrice Bellard
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file mpegaudiodecheader.c
+ * @file
* MPEG Audio header decoder.
*/
-#ifndef MPEGAUDIODECHEADER_H
-#define MPEGAUDIODECHEADER_H
+#ifndef AVCODEC_MPEGAUDIODECHEADER_H
+#define AVCODEC_MPEGAUDIODECHEADER_H
-#include "common.h"
-#include "mpegaudio.h"
+#include "avcodec.h"
+#define MP3_MASK 0xFFFE0CCF
+
+#define MPA_DECODE_HEADER \
+ int frame_size; \
+ int error_protection; \
+ int layer; \
+ int sample_rate; \
+ int sample_rate_index; /* between 0 and 8 */ \
+ int bit_rate; \
+ int nb_channels; \
+ int mode; \
+ int mode_ext; \
+ int lsf;
+
+typedef struct MPADecodeHeader {
+ MPA_DECODE_HEADER
+} MPADecodeHeader;
/* header decoding. MUST check the header before because no
consistency check is done there. Return 1 if free format found and
that the frame size must be computed externally */
-int ff_mpegaudio_decode_header(MPADecodeContext *s, uint32_t header);
+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;
+}
-#endif /* MPEGAUDIODECHEADER_H */
+#endif /* AVCODEC_MPEGAUDIODECHEADER_H */