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add a ff_ac3_parse_header_full() which calls ff_ac3_parse_header() 

and then reads the channel_map stuff

Originally committed as revision 12944 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Bartlomiej Wolowiec 2008-04-24 22:27:13 +00:00
parent 81d5ae6dec
commit 0c79b1402a
5 changed files with 70 additions and 0 deletions
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1
libavcodec/ac3.h
View File

@ -97,6 +97,7 @@ typedef struct {
uint16_t frame_size;
int center_mix_level; ///< Center mix level index
int surround_mix_level; ///< Surround mix level index
uint16_t channel_map;
/** @} */
} AC3HeaderInfo;

29
libavcodec/ac3_parser.c
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@ -136,6 +136,35 @@ int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
return 0;
}
int ff_ac3_parse_header_full(GetBitContext *gbc, AC3HeaderInfo *hdr){
int ret, i;
ret = ff_ac3_parse_header(gbc, hdr);
if(!ret){
if(hdr->bitstream_id>10){
/* Enhanced AC-3 */
skip_bits(gbc, 5); // skip bitstream id
/* skip dialog normalization and compression gain */
for (i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
skip_bits(gbc, 5); // skip dialog normalization
if (get_bits1(gbc)) {
skip_bits(gbc, 8); //skip Compression gain word
}
}
/* dependent stream channel map */
if (hdr->frame_type == EAC3_FRAME_TYPE_DEPENDENT && get_bits1(gbc)) {
hdr->channel_map = get_bits(gbc, 16); //custom channel map
return 0;
}
}
//default channel map based on acmod and lfeon
hdr->channel_map = ff_eac3_default_chmap[hdr->channel_mode];
if(hdr->lfe_on)
hdr->channel_map |= AC3_CHMAP_LFE;
}
return ret;
}
static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
int *need_next_header, int *new_frame_start)
{

11
libavcodec/ac3_parser.h
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@ -46,4 +46,15 @@ typedef enum {
*/
int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);
/**
* Parses AC-3 frame header and sets channel_map
* Parses the header up to the lfeon (channel_map in E-AC-3)
* element, which is the first 52, 54 or 104 bits depending
* on the audio coding mode.
* @param gbc[in] BitContext containing the first 54 bits of the frame.
* @param hdr[out] Pointer to struct where header info is written.
* @return value returned by ff_ac3_parse_header
*/
int ff_ac3_parse_header_full(GetBitContext *gbc, AC3HeaderInfo *hdr);
#endif /* FFMPEG_AC3_PARSER_H */

13
libavcodec/ac3tab.c
View File

@ -247,3 +247,16 @@ const uint8_t ff_ac3_critical_band_size_tab[50]={
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 3, 3, 3,
3, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 24, 24, 24, 24, 24
};
/**
* Default channel map for a dependent substream defined by acmod
*/
const uint16_t ff_eac3_default_chmap[8] = {
AC3_CHMAP_L | AC3_CHMAP_R, // FIXME Ch1+Ch2
AC3_CHMAP_C,
AC3_CHMAP_L | AC3_CHMAP_R,
AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R,
AC3_CHMAP_L | AC3_CHMAP_R | AC3_CHMAP_C_SUR,
AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R | AC3_CHMAP_C_SUR,
AC3_CHMAP_L | AC3_CHMAP_R | AC3_CHMAP_L_SUR | AC3_CHMAP_R_SUR,
AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R | AC3_CHMAP_L_SUR | AC3_CHMAP_R_SUR
};

16
libavcodec/ac3tab.h
View File

@ -39,5 +39,21 @@ extern const uint16_t ff_ac3_db_per_bit_tab[4];
extern const int16_t ff_ac3_floor_tab[8];
extern const uint16_t ff_ac3_fast_gain_tab[8];
extern const uint8_t ff_ac3_critical_band_size_tab[50];
extern const uint16_t ff_eac3_default_chmap[8];
/** Custom channel map locations bitmask
* Other channels described in documentation:
* Lc/Rc pair, Lrs/Rrs pair, Ts, Lsd/Rsd pair,
* Lw/Rw pair, Lvh/Rvh pair, Cvh, Reserved, LFE2
*/
enum CustomChannelMapLocation{
AC3_CHMAP_L= 1<<(15-0),
AC3_CHMAP_C= 1<<(15-1),
AC3_CHMAP_R= 1<<(15-2),
AC3_CHMAP_L_SUR= 1<<(15-3),
AC3_CHMAP_R_SUR = 1<<(15-4),
AC3_CHMAP_C_SUR= 1<<(15-7),
AC3_CHMAP_LFE = 1<<(15-15)
};
#endif /* FFMPEG_AC3TAB_H */