Use shared AC-3 header parsing. Move some initializations to block parsing function.
Originally committed as revision 9773 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles
parent
9ef6039043
commit
9fc1ab722e
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@ -33,8 +33,7 @@
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#include <string.h>
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#include "avcodec.h"
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#include "ac3.h"
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#include "ac3tab.h"
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#include "ac3_parser.h"
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#include "bitstream.h"
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#include "dsputil.h"
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#include "random.h"
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@ -89,9 +88,6 @@ static const float slevs[4] = { LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO, LE
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#define AC3_OUTPUT_LFEON 0x10
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typedef struct {
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uint16_t crc1;
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uint8_t fscod;
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uint8_t acmod;
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uint8_t cmixlev;
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uint8_t surmixlev;
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@ -141,7 +137,8 @@ typedef struct {
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int bit_rate;
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int frame_size;
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int nfchans; //number of channels
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int nchans; //number of total channels
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int nfchans; //number of full-bandwidth channels
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int lfeon; //lfe channel in use
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float dynrng; //dynamic range gain
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@ -320,87 +317,54 @@ static int ac3_decode_init(AVCodecContext *avctx)
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}
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/*********** END INIT FUNCTIONS ***********/
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/* Parse the 'sync_info' from the ac3 bitstream.
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* This function extracts the sync_info from ac3 bitstream.
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/**
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* Parses the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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* GetBitContext within AC3DecodeContext must point to
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* start of the synchronized ac3 bitstream.
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*
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* @param ctx AC3DecodeContext
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* @return Returns framesize, returns 0 if fscod, frmsizecod or bsid is not valid
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*/
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static int ac3_parse_sync_info(AC3DecodeContext *ctx)
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static int ac3_parse_header(AC3DecodeContext *ctx)
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{
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AC3HeaderInfo hdr;
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GetBitContext *gb = &ctx->gb;
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int frmsizecod, bsid;
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int err, i;
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err = ff_ac3_parse_header(gb->buffer, &hdr);
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if(err)
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return err;
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/* get decoding parameters from header info */
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ctx->bit_alloc_params.fscod = hdr.fscod;
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ctx->acmod = hdr.acmod;
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ctx->cmixlev = hdr.cmixlev;
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ctx->surmixlev = hdr.surmixlev;
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ctx->dsurmod = hdr.dsurmod;
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ctx->lfeon = hdr.lfeon;
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ctx->bit_alloc_params.halfratecod = hdr.halfratecod;
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ctx->sampling_rate = hdr.sample_rate;
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ctx->bit_rate = hdr.bit_rate;
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ctx->nchans = hdr.channels;
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ctx->nfchans = ctx->nchans - ctx->lfeon;
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ctx->frame_size = hdr.frame_size;
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ctx->blkoutput = nfchans_tbl[ctx->acmod];
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if(ctx->lfeon)
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ctx->blkoutput |= AC3_OUTPUT_LFEON;
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/* skip over portion of header which has already been read */
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skip_bits(gb, 16); //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
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ctx->crc1 = get_bits(gb, 16);
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ctx->fscod = get_bits(gb, 2);
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if (ctx->fscod == 0x03)
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return 0;
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frmsizecod = get_bits(gb, 6);
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if (frmsizecod >= 38)
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return 0;
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ctx->sampling_rate = ff_ac3_freqs[ctx->fscod];
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ctx->bit_rate = ff_ac3_bitratetab[frmsizecod >> 1];
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/* we include it here in order to determine validity of ac3 frame */
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bsid = get_bits(gb, 5);
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if (bsid > 0x08)
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return 0;
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skip_bits(gb, 3); //skip the bsmod, bsi->bsmod = get_bits(gb, 3);
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switch (ctx->fscod) {
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case 0x00:
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ctx->frame_size = 4 * ctx->bit_rate;
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return ctx->frame_size;
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case 0x01:
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ctx->frame_size = 2 * (320 * ctx->bit_rate / 147 + (frmsizecod & 1));
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return ctx->frame_size;
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case 0x02:
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ctx->frame_size = 6 * ctx->bit_rate;
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return ctx->frame_size;
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skip_bits(gb, 16); // skip crc1
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skip_bits(gb, 8); // skip fscod and frmsizecod
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skip_bits(gb, 11); // skip bsid, bsmod, and acmod
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if(ctx->acmod == AC3_ACMOD_STEREO) {
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skip_bits(gb, 2); // skip dsurmod
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} else {
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if((ctx->acmod & 1) && ctx->acmod != AC3_ACMOD_MONO)
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skip_bits(gb, 2); // skip cmixlev
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if(ctx->acmod & 4)
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skip_bits(gb, 2); // skip surmixlev
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}
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skip_bits1(gb); // skip lfeon
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/* never reached */
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return 0;
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}
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/* Parse bsi from ac3 bitstream.
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* This function extracts the bitstream information (bsi) from ac3 bitstream.
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*
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* @param ctx AC3DecodeContext after processed by ac3_parse_sync_info
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*/
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static void ac3_parse_bsi(AC3DecodeContext *ctx)
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{
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GetBitContext *gb = &ctx->gb;
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int i;
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ctx->cmixlev = 0;
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ctx->surmixlev = 0;
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ctx->dsurmod = 0;
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ctx->nfchans = 0;
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ctx->cpldeltbae = DBA_NONE;
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ctx->cpldeltnseg = 0;
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for (i = 0; i < 5; i++) {
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ctx->deltbae[i] = DBA_NONE;
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ctx->deltnseg[i] = 0;
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}
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ctx->dynrng = 1.0;
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ctx->dynrng2 = 1.0;
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ctx->acmod = get_bits(gb, 3);
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ctx->nfchans = nfchans_tbl[ctx->acmod];
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if (ctx->acmod & 0x01 && ctx->acmod != 0x01)
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ctx->cmixlev = get_bits(gb, 2);
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if (ctx->acmod & 0x04)
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ctx->surmixlev = get_bits(gb, 2);
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if (ctx->acmod == 0x02)
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ctx->dsurmod = get_bits(gb, 2);
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ctx->lfeon = get_bits1(gb);
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/* read the rest of the bsi. read twice for dual mono mode. */
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i = !(ctx->acmod);
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do {
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skip_bits(gb, 5); //skip dialog normalization
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@ -414,6 +378,7 @@ static void ac3_parse_bsi(AC3DecodeContext *ctx)
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skip_bits(gb, 2); //skip copyright bit and original bitstream bit
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/* FIXME: read & use the xbsi1 downmix levels */
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if (get_bits1(gb))
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skip_bits(gb, 14); //skip timecode1
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if (get_bits1(gb))
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@ -425,6 +390,8 @@ static void ac3_parse_bsi(AC3DecodeContext *ctx)
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skip_bits(gb, 8);
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} while(i--);
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}
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return 0;
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}
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/**
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@ -1339,7 +1306,7 @@ static inline void do_imdct(AC3DecodeContext *ctx)
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* and produces the output for the block. This function must
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* be called for each of the six audio block in the ac3 bitstream.
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*/
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static int ac3_parse_audio_block(AC3DecodeContext * ctx)
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static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
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{
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int nfchans = ctx->nfchans;
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int acmod = ctx->acmod;
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@ -1361,11 +1328,17 @@ static int ac3_parse_audio_block(AC3DecodeContext * ctx)
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if (get_bits1(gb)) { /* dynamic range */
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dynrng = get_sbits(gb, 8);
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ctx->dynrng = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]);
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} else if(blk == 0) {
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ctx->dynrng = 1.0;
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}
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if (acmod == 0x00 && get_bits1(gb)) { /* dynamic range 1+1 mode */
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if(acmod == AC3_ACMOD_DUALMONO) { /* dynamic range 1+1 mode */
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if(get_bits1(gb)) {
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dynrng = get_sbits(gb, 8);
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ctx->dynrng2 = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]);
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} else if(blk == 0) {
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ctx->dynrng2 = 1.0;
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}
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}
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get_downmix_coeffs(ctx);
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@ -1559,12 +1532,16 @@ static int ac3_parse_audio_block(AC3DecodeContext * ctx)
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ctx->deltba[i][seg] = get_bits(gb, 3);
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}
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}
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} else if(blk == 0) {
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if(ctx->cplinu)
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ctx->cpldeltbae = DBA_NONE;
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for(i=0; i<nfchans; i++) {
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ctx->deltbae[i] = DBA_NONE;
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}
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}
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if (bit_alloc_flags) {
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/* set bit allocation parameters */
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ctx->bit_alloc_params.fscod = ctx->fscod;
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ctx->bit_alloc_params.halfratecod = 0;
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ctx->bit_alloc_params.sdecay = ff_sdecaytab[ctx->sdcycod];
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ctx->bit_alloc_params.fdecay = ff_fdecaytab[ctx->fdcycod];
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ctx->bit_alloc_params.sgain = ff_sgaintab[ctx->sgaincod];
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@ -1638,17 +1615,12 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
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init_get_bits(&ctx->gb, buf, buf_size * 8);
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//Parse the syncinfo.
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//If 'fscod' or 'bsid' is not valid the decoder shall mute as per the standard.
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if (!ac3_parse_sync_info(ctx)) {
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if (ac3_parse_header(ctx)) {
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av_log(avctx, AV_LOG_ERROR, "\n");
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*data_size = 0;
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return buf_size;
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}
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//Parse the BSI.
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//If 'bsid' is not valid decoder shall not decode the audio as per the standard.
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ac3_parse_bsi(ctx);
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avctx->sample_rate = ctx->sampling_rate;
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avctx->bit_rate = ctx->bit_rate;
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@ -1679,7 +1651,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
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//Parse the Audio Blocks.
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for (i = 0; i < NB_BLOCKS; i++) {
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if (ac3_parse_audio_block(ctx)) {
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if (ac3_parse_audio_block(ctx, i)) {
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av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
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*data_size = 0;
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return ctx->frame_size;
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