3 * Copyright (c) 2007 Ian Caulfield
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
29 #include "libavutil/crc.h"
30 #include "bitstream.h"
32 #include "mlp_parser.h"
35 static const uint8_t mlp_quants[16] = {
36 16, 20, 24, 0, 0, 0, 0, 0,
37 0, 0, 0, 0, 0, 0, 0, 0,
40 static const uint8_t mlp_channels[32] = {
41 1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4,
42 5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
45 static const uint8_t thd_chancount[13] = {
46 // LR C LFE LRs LRvh LRc LRrs Cs Ts LRsd LRw Cvh LFE2
47 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1
50 static int mlp_samplerate(int in)
55 return (in & 8 ? 44100 : 48000) << (in & 7) ;
58 static int truehd_channels(int chanmap)
62 for (i = 0; i < 13; i++)
63 channels += thd_chancount[i] * ((chanmap >> i) & 1);
68 /** Read a major sync info header - contains high level information about
69 * the stream - sample rate, channel arrangement etc. Most of this
70 * information is not actually necessary for decoding, only for playback.
71 * gb must be a freshly initialized GetBitContext with no bits read.
74 int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
79 assert(get_bits_count(gb) == 0);
81 if (gb->size_in_bits < 28 << 3) {
82 av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");
86 checksum = ff_mlp_checksum16(gb->buffer, 26);
87 if (checksum != AV_RL16(gb->buffer+26)) {
88 av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");
92 if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */
95 mh->stream_type = get_bits(gb, 8);
97 if (mh->stream_type == 0xbb) {
98 mh->group1_bits = mlp_quants[get_bits(gb, 4)];
99 mh->group2_bits = mlp_quants[get_bits(gb, 4)];
101 ratebits = get_bits(gb, 4);
102 mh->group1_samplerate = mlp_samplerate(ratebits);
103 mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));
107 mh->channels_mlp = get_bits(gb, 5);
108 } else if (mh->stream_type == 0xba) {
109 mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
112 ratebits = get_bits(gb, 4);
113 mh->group1_samplerate = mlp_samplerate(ratebits);
114 mh->group2_samplerate = 0;
118 mh->channels_thd_stream1 = get_bits(gb, 5);
122 mh->channels_thd_stream2 = get_bits(gb, 13);
126 mh->access_unit_size = 40 << (ratebits & 7);
127 mh->access_unit_size_pow2 = 64 << (ratebits & 7);
129 skip_bits_long(gb, 48);
131 mh->is_vbr = get_bits1(gb);
133 mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
135 mh->num_substreams = get_bits(gb, 4);
137 skip_bits_long(gb, 4 + 11 * 8);
142 typedef struct MLPParseContext
153 static int mlp_parse(AVCodecParserContext *s,
154 AVCodecContext *avctx,
155 const uint8_t **poutbuf, int *poutbuf_size,
156 const uint8_t *buf, int buf_size)
158 MLPParseContext *mp = s->priv_data;
169 // Not in sync - find a major sync header
171 for (i = 0; i < buf_size; i++) {
172 mp->pc.state = (mp->pc.state << 8) | buf[i];
173 if ((mp->pc.state & 0xfffffffe) == 0xf8726fba) {
181 ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
185 ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size);
190 if (mp->bytes_left == 0) {
191 // Find length of this packet
193 /* Copy overread bytes from last frame into buffer. */
194 for(; mp->pc.overread>0; mp->pc.overread--) {
195 mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
198 if (mp->pc.index + buf_size < 2) {
199 ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
203 mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
204 | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
205 mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
206 mp->bytes_left -= mp->pc.index;
209 next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
211 if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
212 mp->bytes_left -= buf_size;
218 sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
221 /* The first nibble of a frame is a parity check of the 4-byte
222 * access unit header and all the 2- or 4-byte substream headers. */
223 // Only check when this isn't a sync frame - syncs have a checksum.
226 for (i = -1; i < mp->num_substreams; i++) {
227 parity_bits ^= buf[p++];
228 parity_bits ^= buf[p++];
230 if (i < 0 || buf[p-2] & 0x80) {
231 parity_bits ^= buf[p++];
232 parity_bits ^= buf[p++];
236 if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
237 av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
244 init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
245 if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
248 #ifdef CONFIG_AUDIO_NONSHORT
249 avctx->bits_per_sample = mh.group1_bits;
250 if (avctx->bits_per_sample > 16)
251 avctx->sample_fmt = SAMPLE_FMT_S32;
253 avctx->sample_rate = mh.group1_samplerate;
254 avctx->frame_size = mh.access_unit_size;
256 if (mh.stream_type == 0xbb) {
258 avctx->channels = mlp_channels[mh.channels_mlp];
259 } else { /* mh.stream_type == 0xba */
261 if (mh.channels_thd_stream2)
262 avctx->channels = truehd_channels(mh.channels_thd_stream2);
264 avctx->channels = truehd_channels(mh.channels_thd_stream1);
267 if (!mh.is_vbr) /* Stream is CBR */
268 avctx->bit_rate = mh.peak_bitrate;
270 mp->num_substreams = mh.num_substreams;
274 *poutbuf_size = buf_size;
283 AVCodecParser mlp_parser = {
285 sizeof(MLPParseContext),