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https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-23 12:43:46 +02:00
change ff_ac3_parse_header() to take a GetBitContext instead of const char*
Originally committed as revision 12922 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Bartlomiej Wolowiec
parent
0ec1eb6906
commit
55736cfbd2
@ -95,6 +95,8 @@ typedef struct {
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uint32_t bit_rate;
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uint8_t channels;
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uint16_t frame_size;
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int center_mix_level; ///< Center mix level index
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int surround_mix_level; ///< Surround mix level index
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/** @} */
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} AC3HeaderInfo;
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@ -33,51 +33,64 @@ static const uint8_t eac3_blocks[4] = {
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1, 2, 3, 6
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};
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/**
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* Table for center mix levels
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* reference: Section 5.4.2.4 cmixlev
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*/
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static const uint8_t center_levels[4] = { 2, 3, 4, 3 };
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int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr)
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/**
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* Table for surround mix levels
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* reference: Section 5.4.2.5 surmixlev
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*/
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static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };
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int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
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{
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GetBitContext gbc;
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int frame_size_code;
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int num_blocks;
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memset(hdr, 0, sizeof(*hdr));
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init_get_bits(&gbc, buf, 54);
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hdr->sync_word = get_bits(&gbc, 16);
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hdr->sync_word = get_bits(gbc, 16);
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if(hdr->sync_word != 0x0B77)
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return AC3_PARSE_ERROR_SYNC;
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/* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
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hdr->bitstream_id = show_bits_long(&gbc, 29) & 0x1F;
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hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
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if(hdr->bitstream_id > 16)
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return AC3_PARSE_ERROR_BSID;
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if(hdr->bitstream_id <= 10) {
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/* Normal AC-3 */
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hdr->crc1 = get_bits(&gbc, 16);
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hdr->sr_code = get_bits(&gbc, 2);
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hdr->crc1 = get_bits(gbc, 16);
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hdr->sr_code = get_bits(gbc, 2);
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if(hdr->sr_code == 3)
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return AC3_PARSE_ERROR_SAMPLE_RATE;
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frame_size_code = get_bits(&gbc, 6);
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frame_size_code = get_bits(gbc, 6);
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if(frame_size_code > 37)
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return AC3_PARSE_ERROR_FRAME_SIZE;
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skip_bits(&gbc, 5); // skip bsid, already got it
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skip_bits(gbc, 5); // skip bsid, already got it
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skip_bits(gbc, 3); // skip bitstream mode
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hdr->channel_mode = get_bits(gbc, 3);
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/* set default mix levels */
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hdr->center_mix_level = 3; // -4.5dB
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hdr->surround_mix_level = 4; // -6.0dB
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skip_bits(&gbc, 3); // skip bitstream mode
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hdr->channel_mode = get_bits(&gbc, 3);
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if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO) {
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skip_bits(&gbc, 2); // skip center mix level
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}
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if(hdr->channel_mode & 4) {
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skip_bits(&gbc, 2); // skip surround mix level
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}
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if(hdr->channel_mode == AC3_CHMODE_STEREO) {
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skip_bits(&gbc, 2); // skip dolby surround mode
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skip_bits(gbc, 2); // skip dsurmod
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} else {
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if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
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hdr->center_mix_level = center_levels[get_bits(gbc, 2)];
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if(hdr->channel_mode & 4)
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hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
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}
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hdr->lfe_on = get_bits1(&gbc);
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hdr->lfe_on = get_bits1(gbc);
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hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
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hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
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@ -88,32 +101,32 @@ int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr)
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} else {
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/* Enhanced AC-3 */
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hdr->crc1 = 0;
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hdr->frame_type = get_bits(&gbc, 2);
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hdr->frame_type = get_bits(gbc, 2);
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if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
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return AC3_PARSE_ERROR_FRAME_TYPE;
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skip_bits(&gbc, 3); // skip substream id
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skip_bits(gbc, 3); // skip substream id
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hdr->frame_size = (get_bits(&gbc, 11) + 1) << 1;
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hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
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if(hdr->frame_size < AC3_HEADER_SIZE)
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return AC3_PARSE_ERROR_FRAME_SIZE;
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hdr->sr_code = get_bits(&gbc, 2);
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hdr->sr_code = get_bits(gbc, 2);
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if (hdr->sr_code == 3) {
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int sr_code2 = get_bits(&gbc, 2);
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int sr_code2 = get_bits(gbc, 2);
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if(sr_code2 == 3)
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return AC3_PARSE_ERROR_SAMPLE_RATE;
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hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
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hdr->sr_shift = 1;
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num_blocks = 6;
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} else {
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num_blocks = eac3_blocks[get_bits(&gbc, 2)];
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num_blocks = eac3_blocks[get_bits(gbc, 2)];
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hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
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hdr->sr_shift = 0;
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}
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hdr->channel_mode = get_bits(&gbc, 3);
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hdr->lfe_on = get_bits1(&gbc);
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hdr->channel_mode = get_bits(gbc, 3);
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hdr->lfe_on = get_bits1(gbc);
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hdr->bit_rate = (uint32_t)(8.0 * hdr->frame_size * hdr->sample_rate /
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(num_blocks * 256.0));
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@ -129,8 +142,10 @@ static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
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int err;
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uint64_t tmp = be2me_64(state);
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AC3HeaderInfo hdr;
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GetBitContext gbc;
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err = ff_ac3_parse_header(((uint8_t *)&tmp)+8-AC3_HEADER_SIZE, &hdr);
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init_get_bits(&gbc, ((uint8_t *)&tmp)+8-AC3_HEADER_SIZE, 54);
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err = ff_ac3_parse_header(&gbc, &hdr);
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if(err < 0)
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return 0;
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@ -24,6 +24,7 @@
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#define FFMPEG_AC3_PARSER_H
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#include "ac3.h"
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#include "bitstream.h"
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typedef enum {
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AC3_PARSE_ERROR_SYNC = -1,
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@ -37,12 +38,12 @@ typedef enum {
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* Parses AC-3 frame header.
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* Parses the header up to the lfeon element, which is the first 52 or 54 bits
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* depending on the audio coding mode.
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* @param buf[in] Array containing the first 7 bytes of the frame.
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* @param gbc[in] BitContext containing the first 54 bits of the frame.
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* @param hdr[out] Pointer to struct where header info is written.
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* @return Returns 0 on success, -1 if there is a sync word mismatch,
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* -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate)
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* element is invalid, or -4 if the frmsizecod (bit rate) element is invalid.
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*/
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int ff_ac3_parse_header(const uint8_t buf[7], AC3HeaderInfo *hdr);
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int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);
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#endif /* FFMPEG_AC3_PARSER_H */
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@ -88,18 +88,6 @@ static const float gain_levels[6] = {
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LEVEL_MINUS_9DB
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};
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/**
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* Table for center mix levels
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* reference: Section 5.4.2.4 cmixlev
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*/
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static const uint8_t center_levels[4] = { 2, 3, 4, 3 };
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/**
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* Table for surround mix levels
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* reference: Section 5.4.2.5 surmixlev
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*/
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static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };
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/**
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* Table for default stereo downmixing coefficients
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* reference: Section 7.8.2 Downmixing Into Two Channels
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@ -315,7 +303,7 @@ static int ac3_parse_header(AC3DecodeContext *s)
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GetBitContext *gbc = &s->gbc;
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int err, i;
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err = ff_ac3_parse_header(gbc->buffer, &hdr);
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err = ff_ac3_parse_header(gbc, &hdr);
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if(err)
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return err;
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@ -333,6 +321,8 @@ static int ac3_parse_header(AC3DecodeContext *s)
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s->fbw_channels = s->channels - s->lfe_on;
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s->lfe_ch = s->fbw_channels + 1;
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s->frame_size = hdr.frame_size;
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s->center_mix_level = hdr.center_mix_level;
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s->surround_mix_level = hdr.surround_mix_level;
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/* set default output to all source channels */
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s->out_channels = s->channels;
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@ -340,25 +330,6 @@ static int ac3_parse_header(AC3DecodeContext *s)
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if(s->lfe_on)
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s->output_mode |= AC3_OUTPUT_LFEON;
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/* set default mix levels */
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s->center_mix_level = 3; // -4.5dB
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s->surround_mix_level = 4; // -6.0dB
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/* skip over portion of header which has already been read */
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skip_bits(gbc, 16); // skip the sync_word
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skip_bits(gbc, 16); // skip crc1
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skip_bits(gbc, 8); // skip fscod and frmsizecod
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skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
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if(s->channel_mode == AC3_CHMODE_STEREO) {
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skip_bits(gbc, 2); // skip dsurmod
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} else {
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if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO)
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s->center_mix_level = center_levels[get_bits(gbc, 2)];
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if(s->channel_mode & 4)
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s->surround_mix_level = surround_levels[get_bits(gbc, 2)];
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}
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skip_bits1(gbc); // skip lfeon
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/* read the rest of the bsi. read twice for dual mono mode. */
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i = !(s->channel_mode);
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do {
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@ -23,6 +23,7 @@
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#include "ac3_parser.h"
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#include "raw.h"
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#include "crc.h"
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#include "bitstream.h"
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#ifdef CONFIG_MUXERS
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/* simple formats */
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@ -419,6 +420,7 @@ static int ac3_probe(AVProbeData *p)
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int max_frames, first_frames = 0, frames;
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uint8_t *buf, *buf2, *end;
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AC3HeaderInfo hdr;
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GetBitContext gbc;
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max_frames = 0;
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buf = p->buf;
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@ -428,7 +430,8 @@ static int ac3_probe(AVProbeData *p)
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buf2 = buf;
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for(frames = 0; buf2 < end; frames++) {
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if(ff_ac3_parse_header(buf2, &hdr) < 0)
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init_get_bits(&gbc, buf2, 54);
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if(ff_ac3_parse_header(&gbc, &hdr) < 0)
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break;
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if(buf2 + hdr.frame_size > end ||
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av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2))
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