James Almer:
> Signed-off-by: James Almer <jamr...@gmail.com>
> ---
> libavcodec/ac3_parser.c | 218 +++++++++++++++++++++++++++++++
> libavcodec/ac3_parser_internal.h | 19 +++
> libavcodec/ac3dec.c | 88 +++----------
> libavcodec/ac3dec.h | 4 +-
> libavcodec/ac3defs.h | 2 +
> libavcodec/eac3dec.c | 154 +++-------------------
> 6 files changed, 279 insertions(+), 206 deletions(-)
>
> diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
> index 69989690dd..1cba847eaa 100644
> --- a/libavcodec/ac3_parser.c
> +++ b/libavcodec/ac3_parser.c
> @@ -73,6 +73,216 @@ int ff_ac3_find_syncword(const uint8_t *buf, int buf_size)
> return i;
> }
>
> +/**
> + * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
> + * GetBitContext within AC3DecodeContext must point to
> + * the start of the synchronized AC-3 bitstream.
> + */
> +static int ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
> +{
> + /* read the rest of the bsi. read twice for dual mono mode. */
> + for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
> + hdr->dialog_normalization[i] = -get_bits(gbc, 5);
> + hdr->compression_exists[i] = get_bits1(gbc);
> + if (hdr->compression_exists[i])
> + hdr->heavy_dynamic_range[i] = get_bits(gbc, 8);
> + if (get_bits1(gbc))
> + skip_bits(gbc, 8); //skip language code
> + if (get_bits1(gbc))
> + skip_bits(gbc, 7); //skip audio production information
> + }
> +
> + skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
> +
> + /* skip the timecodes or parse the Alternate Bit Stream Syntax */
> + if (hdr->bitstream_id != 6) {
> + if (get_bits1(gbc))
> + skip_bits(gbc, 14); //skip timecode1
> + if (get_bits1(gbc))
> + skip_bits(gbc, 14); //skip timecode2
> + } else {
> + if (get_bits1(gbc)) {
> + hdr->preferred_downmix = get_bits(gbc, 2);
> + hdr->center_mix_level_ltrt = get_bits(gbc, 3);
> + hdr->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7);
> + hdr->center_mix_level = get_bits(gbc, 3);
> + hdr->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7);
> + }
> + if (get_bits1(gbc)) {
> + hdr->dolby_surround_ex_mode = get_bits(gbc, 2);
> + hdr->dolby_headphone_mode = get_bits(gbc, 2);
> + skip_bits(gbc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo (1)
> + }
> + }
> +
> + /* skip additional bitstream info */
> + if (get_bits1(gbc)) {
> + int i = get_bits(gbc, 6);
> + do {
> + skip_bits(gbc, 8);
> + } while (i--);
> + }
> +
> + return 0;
> +}
> +
> +static int eac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
> +{
> + if (hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
> + return AC3_PARSE_ERROR_FRAME_TYPE;
> + if (hdr->substreamid)
> + return AC3_PARSE_ERROR_FRAME_TYPE;
> +
> + skip_bits(gbc, 5); // skip bitstream id
> +
> + /* volume control params */
> + for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
> + hdr->dialog_normalization[i] = -get_bits(gbc, 5);
> + hdr->compression_exists[i] = get_bits1(gbc);
> + if (hdr->compression_exists[i])
> + hdr->heavy_dynamic_range[i] = get_bits(gbc, 8);
> + }
> +
> + /* dependent stream channel map */
> + if (hdr->frame_type == EAC3_FRAME_TYPE_DEPENDENT) {
> + if (get_bits1(gbc)) {
> + int64_t channel_layout = 0;
> + int channel_map = get_bits(gbc, 16);
> +
> + for (int i = 0; i < 16; i++)
> + if (channel_map & (1 << (EAC3_MAX_CHANNELS - i - 1)))
> + channel_layout |=
> ff_eac3_custom_channel_map_locations[i][1];
> +
> + if (av_popcount64(channel_layout) > EAC3_MAX_CHANNELS) {
> + return AC3_PARSE_ERROR_CHANNEL_MAP;
> + }
> + hdr->channel_map = channel_map;
> + }
> + }
> +
> + /* mixing metadata */
> + if (get_bits1(gbc)) {
> + /* center and surround mix levels */
> + if (hdr->channel_mode > AC3_CHMODE_STEREO) {
> + hdr->preferred_downmix = get_bits(gbc, 2);
> + if (hdr->channel_mode & 1) {
> + /* if three front channels exist */
> + hdr->center_mix_level_ltrt = get_bits(gbc, 3);
> + hdr->center_mix_level = get_bits(gbc, 3);
> + }
> + if (hdr->channel_mode & 4) {
> + /* if a surround channel exists */
> + hdr->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3,
> 7);
> + hdr->surround_mix_level = av_clip(get_bits(gbc, 3), 3,
> 7);
> + }
> + }
> +
> + /* lfe mix level */
> + if (hdr->lfe_on && (hdr->lfe_mix_level_exists = get_bits1(gbc))) {
> + hdr->lfe_mix_level = get_bits(gbc, 5);
> + }
> +
> + /* info for mixing with other streams and substreams */
> + if (hdr->frame_type == EAC3_FRAME_TYPE_INDEPENDENT) {
> + for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
> + // TODO: apply program scale factor
> + if (get_bits1(gbc)) {
> + skip_bits(gbc, 6); // skip program scale factor
> + }
> + }
> + if (get_bits1(gbc)) {
> + skip_bits(gbc, 6); // skip external program scale factor
> + }
> + /* skip mixing parameter data */
> + switch(get_bits(gbc, 2)) {
> + case 1: skip_bits(gbc, 5); break;
> + case 2: skip_bits(gbc, 12); break;
> + case 3: {
> + int mix_data_size = (get_bits(gbc, 5) + 2) << 3;
> + skip_bits_long(gbc, mix_data_size);
> + break;
> + }
> + }
> + /* skip pan information for mono or dual mono source */
> + if (hdr->channel_mode < AC3_CHMODE_STEREO) {
> + for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
> + if (get_bits1(gbc)) {
> + /* note: this is not in the ATSC A/52B specification
> + reference: ETSI TS 102 366 V1.1.1
> + section: E.1.3.1.25 */
> + skip_bits(gbc, 8); // skip pan mean direction index
> + skip_bits(gbc, 6); // skip reserved paninfo bits
> + }
> + }
> + }
> + /* skip mixing configuration information */
> + if (get_bits1(gbc)) {
> + for (int i = 0; i < hdr->num_blocks; i++) {
> + if (hdr->num_blocks == 1 || get_bits1(gbc)) {
> + skip_bits(gbc, 5);
> + }
> + }
> + }
> + }
> + }
> +
> + /* informational metadata */
> + if (get_bits1(gbc)) {
> + hdr->bitstream_mode = get_bits(gbc, 3);
> + skip_bits(gbc, 2); // skip copyright bit and original bitstream bit
> + if (hdr->channel_mode == AC3_CHMODE_STEREO) {
> + hdr->dolby_surround_mode = get_bits(gbc, 2);
> + hdr->dolby_headphone_mode = get_bits(gbc, 2);
> + }
> + if (hdr->channel_mode >= AC3_CHMODE_2F2R) {
> + hdr->dolby_surround_ex_mode = get_bits(gbc, 2);
> + }
> + for (int i = 0; i < (hdr->channel_mode ? 1 : 2); i++) {
> + if (get_bits1(gbc)) {
> + skip_bits(gbc, 8); // skip mix level, room type, and A/D
> converter type
> + }
> + }
> + if (hdr->sr_code != EAC3_SR_CODE_REDUCED) {
> + skip_bits1(gbc); // skip source sample rate code
> + }
> + }
> +
> + /* converter synchronization flag
> + If frames are less than six blocks, this bit should be turned on
> + once every 6 blocks to indicate the start of a frame set.
> + reference: RFC 4598, Section 2.1.3 Frame Sets */
> + if (hdr->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && hdr->num_blocks !=
> 6) {
> + skip_bits1(gbc); // skip converter synchronization flag
> + }
> +
> + /* original frame size code if this stream was converted from AC-3 */
> + if (hdr->frame_type == EAC3_FRAME_TYPE_AC3_CONVERT &&
> + (hdr->num_blocks == 6 || get_bits1(gbc))) {
> + skip_bits(gbc, 6); // skip frame size code
> + }
> +
> + /* additional bitstream info */
> + if (get_bits1(gbc)) {
> + int addbsil = get_bits(gbc, 6);
> + for (int i = 0; i < addbsil + 1; i++) {
> + if (i == 0) {
> + /* In this 8 bit chunk, the LSB is equal to
> flag_ec3_extension_type_a
> + which can be used to detect Atmos presence */
> + skip_bits(gbc, 7);
> + hdr->eac3_extension_type_a = get_bits1(gbc);
> + if (hdr->eac3_extension_type_a) {
> + hdr->complexity_index_type_a = get_bits(gbc, 8);
> + i++;
> + }
> + } else {
> + skip_bits(gbc, 8); // skip additional bit stream info
> + }
> + }
> + }
> +
> + return 0;
> +}
> +
> int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
> {
> int frame_size_code;
> @@ -133,6 +343,10 @@ int ff_ac3_parse_header(GetBitContext *gbc,
> AC3HeaderInfo *hdr)
> hdr->frame_size =
> ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2;
> hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT;
> //EAC3_FRAME_TYPE_INDEPENDENT;
> hdr->substreamid = 0;
> +
> + int ret = ac3_parse_header(gbc, hdr);
> + if (ret < 0)
> + return ret;
> } else {
> /* Enhanced AC-3 */
> hdr->crc1 = 0;
> @@ -165,6 +379,10 @@ int ff_ac3_parse_header(GetBitContext *gbc,
> AC3HeaderInfo *hdr)
> hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate /
> (hdr->num_blocks * 256);
> hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
> +
> + int ret = eac3_parse_header(gbc, hdr);
> + if (ret < 0)
> + return ret;
> }
> hdr->channel_layout = ff_ac3_channel_layout_tab[hdr->channel_mode];
> if (hdr->lfe_on)
> diff --git a/libavcodec/ac3_parser_internal.h
> b/libavcodec/ac3_parser_internal.h
> index 46814bfb1f..ab5df34003 100644
> --- a/libavcodec/ac3_parser_internal.h
> +++ b/libavcodec/ac3_parser_internal.h
> @@ -46,6 +46,7 @@ typedef struct AC3HeaderInfo {
> int substreamid; ///< substream identification
> int center_mix_level; ///< Center mix level index
> int surround_mix_level; ///< Surround mix level index
> + uint8_t channel_map_present;
> uint16_t channel_map;
> int num_blocks; ///< number of audio blocks
> int dolby_surround_mode;
> @@ -62,6 +63,23 @@ typedef struct AC3HeaderInfo {
> uint64_t channel_layout;
> int8_t ac3_bit_rate_code;
> /** @} */
> +
> + /** @name enhanced eac3 extension coded elements
> + * @{
> + */
> + int8_t dialog_normalization[2];
> + uint8_t compression_exists[2];
> + uint8_t heavy_dynamic_range[2];
> + uint8_t center_mix_level_ltrt; ///< Center mix level index
> + uint8_t surround_mix_level_ltrt; ///< Surround mix level index
> + uint8_t dolby_headphone_mode;
> + uint8_t dolby_surround_ex_mode;
> + uint8_t lfe_mix_level_exists;
> + uint8_t lfe_mix_level;
> + uint8_t preferred_downmix;
> + uint8_t eac3_extension_type_a;
> + uint8_t complexity_index_type_a;
> + /** @} */
> } AC3HeaderInfo;
>
> typedef enum {
> @@ -71,6 +89,7 @@ typedef enum {
> AC3_PARSE_ERROR_FRAME_SIZE = -0x4030c0a,
> AC3_PARSE_ERROR_FRAME_TYPE = -0x5030c0a,
> AC3_PARSE_ERROR_CRC = -0x6030c0a,
> + AC3_PARSE_ERROR_CHANNEL_MAP = -0x7030c0a,
> } AC3ParseError;
>
> /**
> diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
> index 5eacab4475..2f0e7f5344 100644
> --- a/libavcodec/ac3dec.c
> +++ b/libavcodec/ac3dec.c
> @@ -156,72 +156,6 @@ static av_cold void ac3_decode_flush(AVCodecContext
> *avctx)
> av_lfg_init(&s->dith_state, 0);
> }
>
> -/**
> - * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
> - * GetBitContext within AC3DecodeContext must point to
> - * the start of the synchronized AC-3 bitstream.
> - */
> -static int ac3_parse_header(AC3DecodeContext *s)
> -{
> - GetBitContext *gbc = &s->gbc;
> - int i;
> -
> - /* read the rest of the bsi. read twice for dual mono mode. */
> - i = !s->channel_mode;
> - do {
> - s->dialog_normalization[(!s->channel_mode)-i] = -get_bits(gbc, 5);
> - if (s->dialog_normalization[(!s->channel_mode)-i] == 0) {
> - s->dialog_normalization[(!s->channel_mode)-i] = -31;
> - }
> - if (s->target_level != 0) {
> - s->level_gain[(!s->channel_mode)-i] = powf(2.0f,
> - (float)(s->target_level -
> - s->dialog_normalization[(!s->channel_mode)-i])/6.0f);
> - }
> - if (s->compression_exists[(!s->channel_mode)-i] = get_bits1(gbc)) {
> - s->heavy_dynamic_range[(!s->channel_mode)-i] =
> - AC3_HEAVY_RANGE(get_bits(gbc, 8));
> - }
> - if (get_bits1(gbc))
> - skip_bits(gbc, 8); //skip language code
> - if (get_bits1(gbc))
> - skip_bits(gbc, 7); //skip audio production information
> - } while (i--);
> -
> - skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
> -
> - /* skip the timecodes or parse the Alternate Bit Stream Syntax */
> - if (s->bitstream_id != 6) {
> - if (get_bits1(gbc))
> - skip_bits(gbc, 14); //skip timecode1
> - if (get_bits1(gbc))
> - skip_bits(gbc, 14); //skip timecode2
> - } else {
> - if (get_bits1(gbc)) {
> - s->preferred_downmix = get_bits(gbc, 2);
> - s->center_mix_level_ltrt = get_bits(gbc, 3);
> - s->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7);
> - s->center_mix_level = get_bits(gbc, 3);
> - s->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7);
> - }
> - if (get_bits1(gbc)) {
> - s->dolby_surround_ex_mode = get_bits(gbc, 2);
> - s->dolby_headphone_mode = get_bits(gbc, 2);
> - skip_bits(gbc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo (1)
> - }
> - }
> -
> - /* skip additional bitstream info */
> - if (get_bits1(gbc)) {
> - i = get_bits(gbc, 6);
> - do {
> - skip_bits(gbc, 8);
> - } while (i--);
> - }
> -
> - return 0;
> -}
> -
> /**
> * Common function to parse AC-3 or E-AC-3 frame header
> */
> @@ -281,10 +215,25 @@ static int parse_frame_header(AC3DecodeContext *s)
> s->dba_syntax = 1;
> s->skip_syntax = 1;
> memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
> - return ac3_parse_header(s);
> + /* volume control params */
> + for (int i = 0; i < (s->channel_mode ? 1 : 2); i++) {
> + s->dialog_normalization[i] = hdr.dialog_normalization[i];
> + if (s->dialog_normalization[i] == 0) {
> + s->dialog_normalization[i] = -31;
> + }
> + if (s->target_level != 0) {
> + s->level_gain[i] = powf(2.0f,
> + (float)(s->target_level -
> s->dialog_normalization[i])/6.0f);
> + }
> + s->compression_exists[i] = hdr.compression_exists[i];
> + if (s->compression_exists[i]) {
> + s->heavy_dynamic_range[i] =
> AC3_HEAVY_RANGE(hdr.heavy_dynamic_range[i]);
> + }
> + }
> + return 0;
> } else if (CONFIG_EAC3_DECODER) {
> s->eac3 = 1;
> - return ff_eac3_parse_header(s);
> + return ff_eac3_parse_header(s, &hdr);
> } else {
> av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n");
> return AVERROR(ENOSYS);
> @@ -1469,6 +1418,9 @@ dependent_frame:
> av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
> }
> break;
> + case AC3_PARSE_ERROR_CHANNEL_MAP:
> + av_log(avctx, AV_LOG_ERROR, "invalid channel map\n");
> + return AVERROR_INVALIDDATA;
> case AC3_PARSE_ERROR_CRC:
> break;
> default: // Normal AVERROR do not try to recover.
> diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
> index 4042a99b80..a099264475 100644
> --- a/libavcodec/ac3dec.h
> +++ b/libavcodec/ac3dec.h
> @@ -260,11 +260,13 @@ typedef struct AC3DecodeContext {
> ///@}
> } AC3DecodeContext;
>
> +struct AC3HeaderInfo;
> +
> /**
> * Parse the E-AC-3 frame header.
> * This parses both the bit stream info and audio frame header.
> */
> -static int ff_eac3_parse_header(AC3DecodeContext *s);
> +static int ff_eac3_parse_header(AC3DecodeContext *s, const struct
> AC3HeaderInfo *hdr);
>
> /**
> * Decode mantissas in a single channel for the entire frame.
> diff --git a/libavcodec/ac3defs.h b/libavcodec/ac3defs.h
> index f9b1be059f..8d6a58d21f 100644
> --- a/libavcodec/ac3defs.h
> +++ b/libavcodec/ac3defs.h
> @@ -34,6 +34,8 @@
> #define AC3_CRITICAL_BANDS 50
> #define AC3_MAX_CPL_BANDS 18
>
> +#define EAC3_SR_CODE_REDUCED 3
> +
> /* pre-defined gain values */
> #define LEVEL_PLUS_3DB M_SQRT2
> #define LEVEL_PLUS_1POINT5DB 1.1892071150027209
> diff --git a/libavcodec/eac3dec.c b/libavcodec/eac3dec.c
> index 2b3bffda6e..c5095b1917 100644
> --- a/libavcodec/eac3dec.c
> +++ b/libavcodec/eac3dec.c
> @@ -53,8 +53,6 @@ typedef enum {
> EAC3_GAQ_124
> } EAC3GaqMode;
>
> -#define EAC3_SR_CODE_REDUCED 3
> -
> static void ff_eac3_apply_spectral_extension(AC3DecodeContext *s)
> {
> int bin, bnd, ch, i;
> @@ -287,7 +285,7 @@ static void
> ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch)
> }
> }
>
> -static int ff_eac3_parse_header(AC3DecodeContext *s)
> +static int ff_eac3_parse_header(AC3DecodeContext *s, const AC3HeaderInfo
> *hdr)
> {
> int i, blk, ch;
> int ac3_exponent_strategy, parse_aht_info, parse_spx_atten_data;
> @@ -323,11 +321,10 @@ static int ff_eac3_parse_header(AC3DecodeContext *s)
> avpriv_request_sample(s->avctx, "Reduced sampling rate");
> return AVERROR_PATCHWELCOME;
> }
> - skip_bits(gbc, 5); // skip bitstream id
>
> /* volume control params */
> for (i = 0; i < (s->channel_mode ? 1 : 2); i++) {
> - s->dialog_normalization[i] = -get_bits(gbc, 5);
> + s->dialog_normalization[i] = hdr->dialog_normalization[i];
> if (s->dialog_normalization[i] == 0) {
> s->dialog_normalization[i] = -31;
> }
> @@ -335,147 +332,30 @@ static int ff_eac3_parse_header(AC3DecodeContext *s)
> s->level_gain[i] = powf(2.0f,
> (float)(s->target_level - s->dialog_normalization[i])/6.0f);
> }
> - s->compression_exists[i] = get_bits1(gbc);
> - if (s->compression_exists[i]) {
> - s->heavy_dynamic_range[i] = AC3_HEAVY_RANGE(get_bits(gbc, 8));
> + if (hdr->compression_exists[i]) {
> + s->heavy_dynamic_range[i] =
> AC3_HEAVY_RANGE(hdr->heavy_dynamic_range[i]);
> }
> }
>
> - /* dependent stream channel map */
> - if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT) {
> - if (get_bits1(gbc)) {
> - int64_t channel_layout = 0;
> - int channel_map = get_bits(gbc, 16);
> - av_log(s->avctx, AV_LOG_DEBUG, "channel_map: %0X\n",
> channel_map);
> -
> - for (i = 0; i < 16; i++)
> - if (channel_map & (1 << (EAC3_MAX_CHANNELS - i - 1)))
> - channel_layout |=
> ff_eac3_custom_channel_map_locations[i][1];
> -
> - if (av_popcount64(channel_layout) > EAC3_MAX_CHANNELS) {
> - return AVERROR_INVALIDDATA;
> - }
> - s->channel_map = channel_map;
> - }
> - }
> + s->channel_map = hdr->channel_map;
>
> /* mixing metadata */
> - if (get_bits1(gbc)) {
> - /* center and surround mix levels */
> - if (s->channel_mode > AC3_CHMODE_STEREO) {
> - s->preferred_downmix = get_bits(gbc, 2);
> - if (s->channel_mode & 1) {
> - /* if three front channels exist */
> - s->center_mix_level_ltrt = get_bits(gbc, 3);
> - s->center_mix_level = get_bits(gbc, 3);
> - }
> - if (s->channel_mode & 4) {
> - /* if a surround channel exists */
> - s->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7);
> - s->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7);
> - }
> - }
> -
> - /* lfe mix level */
> - if (s->lfe_on && (s->lfe_mix_level_exists = get_bits1(gbc))) {
> - s->lfe_mix_level = get_bits(gbc, 5);
> - }
> -
> - /* info for mixing with other streams and substreams */
> - if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT) {
> - for (i = 0; i < (s->channel_mode ? 1 : 2); i++) {
> - // TODO: apply program scale factor
> - if (get_bits1(gbc)) {
> - skip_bits(gbc, 6); // skip program scale factor
> - }
> - }
> - if (get_bits1(gbc)) {
> - skip_bits(gbc, 6); // skip external program scale factor
> - }
> - /* skip mixing parameter data */
> - switch(get_bits(gbc, 2)) {
> - case 1: skip_bits(gbc, 5); break;
> - case 2: skip_bits(gbc, 12); break;
> - case 3: {
> - int mix_data_size = (get_bits(gbc, 5) + 2) << 3;
> - skip_bits_long(gbc, mix_data_size);
> - break;
> - }
> - }
> - /* skip pan information for mono or dual mono source */
> - if (s->channel_mode < AC3_CHMODE_STEREO) {
> - for (i = 0; i < (s->channel_mode ? 1 : 2); i++) {
> - if (get_bits1(gbc)) {
> - /* note: this is not in the ATSC A/52B specification
> - reference: ETSI TS 102 366 V1.1.1
> - section: E.1.3.1.25 */
> - skip_bits(gbc, 8); // skip pan mean direction index
> - skip_bits(gbc, 6); // skip reserved paninfo bits
> - }
> - }
> - }
> - /* skip mixing configuration information */
> - if (get_bits1(gbc)) {
> - for (blk = 0; blk < s->num_blocks; blk++) {
> - if (s->num_blocks == 1 || get_bits1(gbc)) {
> - skip_bits(gbc, 5);
> - }
> - }
> - }
> - }
> - }
> + s->preferred_downmix = hdr->preferred_downmix;
> + s->center_mix_level_ltrt = hdr->center_mix_level_ltrt;
> + s->center_mix_level = hdr->center_mix_level;
> + s->surround_mix_level_ltrt = hdr->surround_mix_level_ltrt;
> + s->surround_mix_level = hdr->surround_mix_level;
> + s->lfe_mix_level_exists = hdr->lfe_mix_level_exists;
> + s->lfe_mix_level = hdr->lfe_mix_level;
> + s->dolby_surround_mode = hdr->dolby_surround_mode;
> + s->dolby_headphone_mode = hdr->dolby_headphone_mode;
> + s->dolby_surround_ex_mode = hdr->dolby_surround_ex_mode;
>
> /* informational metadata */
> - if (get_bits1(gbc)) {
> - s->bitstream_mode = get_bits(gbc, 3);
> - skip_bits(gbc, 2); // skip copyright bit and original bitstream bit
> - if (s->channel_mode == AC3_CHMODE_STEREO) {
> - s->dolby_surround_mode = get_bits(gbc, 2);
> - s->dolby_headphone_mode = get_bits(gbc, 2);
> - }
> - if (s->channel_mode >= AC3_CHMODE_2F2R) {
> - s->dolby_surround_ex_mode = get_bits(gbc, 2);
> - }
> - for (i = 0; i < (s->channel_mode ? 1 : 2); i++) {
> - if (get_bits1(gbc)) {
> - skip_bits(gbc, 8); // skip mix level, room type, and A/D
> converter type
> - }
> - }
> - if (s->bit_alloc_params.sr_code != EAC3_SR_CODE_REDUCED) {
> - skip_bits1(gbc); // skip source sample rate code
> - }
> - }
> -
> - /* converter synchronization flag
> - If frames are less than six blocks, this bit should be turned on
> - once every 6 blocks to indicate the start of a frame set.
> - reference: RFC 4598, Section 2.1.3 Frame Sets */
> - if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && s->num_blocks != 6) {
> - skip_bits1(gbc); // skip converter synchronization flag
> - }
> -
> - /* original frame size code if this stream was converted from AC-3 */
> - if (s->frame_type == EAC3_FRAME_TYPE_AC3_CONVERT &&
> - (s->num_blocks == 6 || get_bits1(gbc))) {
> - skip_bits(gbc, 6); // skip frame size code
> - }
> + s->bitstream_mode = hdr->bitstream_mode;
>
> /* additional bitstream info */
> - if (get_bits1(gbc)) {
> - int addbsil = get_bits(gbc, 6);
> - for (i = 0; i < addbsil + 1; i++) {
> - if (i == 0) {
> - /* In this 8 bit chunk, the LSB is equal to
> flag_ec3_extension_type_a
> - which can be used to detect Atmos presence */
> - skip_bits(gbc, 7);
> - if (get_bits1(gbc)) {
> - s->eac3_extension_type_a = 1;
> - }
> - } else {
> - skip_bits(gbc, 8); // skip additional bit stream info
> - }
> - }
> - }
> + s->eac3_extension_type_a = hdr->eac3_extension_type_a;
>
> /* audio frame syntax flags, strategy data, and per-frame data */
>
Seems like av_ac3_parse_header() simply presumes the buffer to be padded
(like av_adts_header_parse() until 6c812a80ddfadb), although this is not
a documented requirement. Your patch will make it worse, because it
parses more.
- Andreas
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