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Diffstat (limited to 'ffmpeg1/libavcodec/ac3_parser.c')
-rw-r--r--ffmpeg1/libavcodec/ac3_parser.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/ac3_parser.c b/ffmpeg1/libavcodec/ac3_parser.c
new file mode 100644
index 0000000..8dc4c0d
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+++ b/ffmpeg1/libavcodec/ac3_parser.c
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+/*
+ * AC-3 parser
+ * Copyright (c) 2003 Fabrice Bellard
+ * Copyright (c) 2003 Michael Niedermayer
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/channel_layout.h"
+#include "parser.h"
+#include "ac3_parser.h"
+#include "aac_ac3_parser.h"
+#include "get_bits.h"
+
+
+#define AC3_HEADER_SIZE 7
+
+
+static const uint8_t eac3_blocks[4] = {
+ 1, 2, 3, 6
+};
+
+/**
+ * Table for center mix levels
+ * reference: Section 5.4.2.4 cmixlev
+ */
+static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
+
+/**
+ * Table for surround mix levels
+ * reference: Section 5.4.2.5 surmixlev
+ */
+static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
+
+
+int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
+{
+ int frame_size_code;
+
+ memset(hdr, 0, sizeof(*hdr));
+
+ hdr->sync_word = get_bits(gbc, 16);
+ if(hdr->sync_word != 0x0B77)
+ return AAC_AC3_PARSE_ERROR_SYNC;
+
+ /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
+ hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
+ if(hdr->bitstream_id > 16)
+ return AAC_AC3_PARSE_ERROR_BSID;
+
+ hdr->num_blocks = 6;
+
+ /* set default mix levels */
+ hdr->center_mix_level = 5; // -4.5dB
+ hdr->surround_mix_level = 6; // -6.0dB
+
+ if(hdr->bitstream_id <= 10) {
+ /* Normal AC-3 */
+ hdr->crc1 = get_bits(gbc, 16);
+ hdr->sr_code = get_bits(gbc, 2);
+ if(hdr->sr_code == 3)
+ return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
+
+ frame_size_code = get_bits(gbc, 6);
+ if(frame_size_code > 37)
+ return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
+
+ skip_bits(gbc, 5); // skip bsid, already got it
+
+ hdr->bitstream_mode = get_bits(gbc, 3);
+ hdr->channel_mode = get_bits(gbc, 3);
+
+ if(hdr->channel_mode == AC3_CHMODE_STEREO) {
+ skip_bits(gbc, 2); // skip dsurmod
+ } else {
+ if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
+ hdr-> center_mix_level = center_levels[get_bits(gbc, 2)];
+ if(hdr->channel_mode & 4)
+ hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
+ }
+ hdr->lfe_on = get_bits1(gbc);
+
+ hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
+ hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
+ hdr->bit_rate = (ff_ac3_bitrate_tab[frame_size_code>>1] * 1000) >> hdr->sr_shift;
+ hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
+ 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;
+ } else {
+ /* Enhanced AC-3 */
+ hdr->crc1 = 0;
+ hdr->frame_type = get_bits(gbc, 2);
+ if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
+ return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
+
+ hdr->substreamid = get_bits(gbc, 3);
+
+ hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
+ if(hdr->frame_size < AC3_HEADER_SIZE)
+ return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
+
+ hdr->sr_code = get_bits(gbc, 2);
+ if (hdr->sr_code == 3) {
+ int sr_code2 = get_bits(gbc, 2);
+ if(sr_code2 == 3)
+ return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
+ hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
+ hdr->sr_shift = 1;
+ } else {
+ hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)];
+ hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
+ hdr->sr_shift = 0;
+ }
+
+ hdr->channel_mode = get_bits(gbc, 3);
+ hdr->lfe_on = get_bits1(gbc);
+
+ hdr->bit_rate = (uint32_t)(8.0 * hdr->frame_size * hdr->sample_rate /
+ (hdr->num_blocks * 256.0));
+ hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
+ }
+ hdr->channel_layout = avpriv_ac3_channel_layout_tab[hdr->channel_mode];
+ if (hdr->lfe_on)
+ hdr->channel_layout |= AV_CH_LOW_FREQUENCY;
+
+ return 0;
+}
+
+static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
+ int *need_next_header, int *new_frame_start)
+{
+ int err;
+ union {
+ uint64_t u64;
+ uint8_t u8[8];
+ } tmp = { av_be2ne64(state) };
+ AC3HeaderInfo hdr;
+ GetBitContext gbc;
+
+ init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54);
+ err = avpriv_ac3_parse_header(&gbc, &hdr);
+
+ if(err < 0)
+ return 0;
+
+ hdr_info->sample_rate = hdr.sample_rate;
+ hdr_info->bit_rate = hdr.bit_rate;
+ hdr_info->channels = hdr.channels;
+ hdr_info->channel_layout = hdr.channel_layout;
+ hdr_info->samples = hdr.num_blocks * 256;
+ hdr_info->service_type = hdr.bitstream_mode;
+ if (hdr.bitstream_mode == 0x7 && hdr.channels > 1)
+ hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
+ if(hdr.bitstream_id>10)
+ hdr_info->codec_id = AV_CODEC_ID_EAC3;
+ else if (hdr_info->codec_id == AV_CODEC_ID_NONE)
+ hdr_info->codec_id = AV_CODEC_ID_AC3;
+
+ *need_next_header = (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT);
+ *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT);
+ return hdr.frame_size;
+}
+
+static av_cold int ac3_parse_init(AVCodecParserContext *s1)
+{
+ AACAC3ParseContext *s = s1->priv_data;
+ s->header_size = AC3_HEADER_SIZE;
+ s->sync = ac3_sync;
+ return 0;
+}
+
+
+AVCodecParser ff_ac3_parser = {
+ .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 },
+ .priv_data_size = sizeof(AACAC3ParseContext),
+ .parser_init = ac3_parse_init,
+ .parser_parse = ff_aac_ac3_parse,
+ .parser_close = ff_parse_close,
+};
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