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flacdec: Add a shared function for parsing a FLAC metadata block header.

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Originally committed as revision 17851 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2009-03-06 01:25:11 +00:00
parent e0c98063e7
commit 5b63d33d7d
2 changed files with 26 additions and 6 deletions
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10
libavcodec/flac.h
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@ -83,4 +83,14 @@ int ff_flac_is_extradata_valid(AVCodecContext *avctx,
enum FLACExtradataFormat *format,
uint8_t **streaminfo_start);
/**
* Parse the metadata block parameters from the header.
* @param[in] block_header header data, at least 4 bytes
* @param[out] last indicator for last metadata block
* @param[out] type metadata block type
* @param[out] size metadata block size
*/
void ff_flac_parse_block_header(const uint8_t *block_header,
int *last, int *type, int *size);
#endif /* AVCODEC_FLAC_H */

22
libavcodec/flacdec.c
View File

@ -220,6 +220,18 @@ void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
dump_headers(avctx, s);
}
void ff_flac_parse_block_header(const uint8_t *block_header,
int *last, int *type, int *size)
{
int tmp = bytestream_get_byte(&block_header);
if (last)
*last = tmp & 0x80;
if (type)
*type = tmp & 0x7F;
if (size)
*size = bytestream_get_be24(&block_header);
}
/**
* Parse the STREAMINFO from an inline header.
* @param s the flac decoding context
@ -235,14 +247,12 @@ static int parse_streaminfo(FLACContext *s, const uint8_t *buf, int buf_size)
/* need more data */
return 0;
}
buf += 4;
metadata_type = bytestream_get_byte(&buf) & 0x7F;
metadata_size = bytestream_get_be24(&buf);
ff_flac_parse_block_header(&buf[4], NULL, &metadata_type, &metadata_size);
if (metadata_type != FLAC_METADATA_TYPE_STREAMINFO ||
metadata_size != FLAC_STREAMINFO_SIZE) {
return AVERROR_INVALIDDATA;
}
ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, buf);
ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, &buf[8]);
allocate_buffers(s);
s->got_streaminfo = 1;
@ -262,8 +272,8 @@ static int get_metadata_size(const uint8_t *buf, int buf_size)
buf += 4;
do {
metadata_last = bytestream_get_byte(&buf) & 0x80;
metadata_size = bytestream_get_be24(&buf);
ff_flac_parse_block_header(buf, &metadata_last, NULL, &metadata_size);
buf += 4;
if (buf + metadata_size > buf_end) {
/* need more data in order to read the complete header */
return 0;