3 * Copyright (c) 2007 Ian Caulfield
5 * This file is part of Libav.
7 * Libav 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 * Libav 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 Libav; 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"
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 uint64_t mlp_layout[32] = {
50 AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,
51 AV_CH_LAYOUT_2_1|AV_CH_LOW_FREQUENCY,
52 AV_CH_LAYOUT_2_2|AV_CH_LOW_FREQUENCY,
53 AV_CH_LAYOUT_SURROUND,
56 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
57 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,
61 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
62 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,
64 AV_CH_LAYOUT_2_2|AV_CH_LOW_FREQUENCY,
67 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
70 static const uint8_t thd_chancount[13] = {
71 // LR C LFE LRs LRvh LRc LRrs Cs Ts LRsd LRw Cvh LFE2
72 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1
75 static const uint64_t thd_layout[13] = {
76 AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT, // LR
77 AV_CH_FRONT_CENTER, // C
78 AV_CH_LOW_FREQUENCY, // LFE
79 AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT, // LRs
80 AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT, // LRvh
81 AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT, // LRc
82 AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT, // LRrs
83 AV_CH_BACK_CENTER, // Cs
84 AV_CH_TOP_BACK_CENTER, // Ts
85 AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT, // LRsd
86 AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER, // LRw
87 AV_CH_TOP_BACK_CENTER, // Cvh
88 AV_CH_LOW_FREQUENCY // LFE2
91 static int mlp_samplerate(int in)
96 return (in & 8 ? 44100 : 48000) << (in & 7) ;
99 static int truehd_channels(int chanmap)
103 for (i = 0; i < 13; i++)
104 channels += thd_chancount[i] * ((chanmap >> i) & 1);
109 static int64_t truehd_layout(int chanmap)
113 for (i = 0; i < 13; i++)
114 layout |= thd_layout[i] * ((chanmap >> i) & 1);
119 /** Read a major sync info header - contains high level information about
120 * the stream - sample rate, channel arrangement etc. Most of this
121 * information is not actually necessary for decoding, only for playback.
122 * gb must be a freshly initialized GetBitContext with no bits read.
125 int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
130 assert(get_bits_count(gb) == 0);
132 if (gb->size_in_bits < 28 << 3) {
133 av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");
137 checksum = ff_mlp_checksum16(gb->buffer, 26);
138 if (checksum != AV_RL16(gb->buffer+26)) {
139 av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");
143 if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */
146 mh->stream_type = get_bits(gb, 8);
148 if (mh->stream_type == 0xbb) {
149 mh->group1_bits = mlp_quants[get_bits(gb, 4)];
150 mh->group2_bits = mlp_quants[get_bits(gb, 4)];
152 ratebits = get_bits(gb, 4);
153 mh->group1_samplerate = mlp_samplerate(ratebits);
154 mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));
158 mh->channels_mlp = get_bits(gb, 5);
159 } else if (mh->stream_type == 0xba) {
160 mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
163 ratebits = get_bits(gb, 4);
164 mh->group1_samplerate = mlp_samplerate(ratebits);
165 mh->group2_samplerate = 0;
169 mh->channels_thd_stream1 = get_bits(gb, 5);
173 mh->channels_thd_stream2 = get_bits(gb, 13);
177 mh->access_unit_size = 40 << (ratebits & 7);
178 mh->access_unit_size_pow2 = 64 << (ratebits & 7);
180 skip_bits_long(gb, 48);
182 mh->is_vbr = get_bits1(gb);
184 mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
186 mh->num_substreams = get_bits(gb, 4);
188 skip_bits_long(gb, 4 + 11 * 8);
193 typedef struct MLPParseContext
204 static av_cold int mlp_init(AVCodecParserContext *s)
210 static int mlp_parse(AVCodecParserContext *s,
211 AVCodecContext *avctx,
212 const uint8_t **poutbuf, int *poutbuf_size,
213 const uint8_t *buf, int buf_size)
215 MLPParseContext *mp = s->priv_data;
226 // Not in sync - find a major sync header
228 for (i = 0; i < buf_size; i++) {
229 mp->pc.state = (mp->pc.state << 8) | buf[i];
230 if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
231 // ignore if we do not have the data for the start of header
232 mp->pc.index + i >= 7) {
240 ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
244 ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size);
249 if (mp->bytes_left == 0) {
250 // Find length of this packet
252 /* Copy overread bytes from last frame into buffer. */
253 for(; mp->pc.overread>0; mp->pc.overread--) {
254 mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
257 if (mp->pc.index + buf_size < 2) {
258 ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
262 mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
263 | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
264 mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
265 mp->bytes_left -= mp->pc.index;
268 next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
270 if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
271 mp->bytes_left -= buf_size;
277 sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
280 /* The first nibble of a frame is a parity check of the 4-byte
281 * access unit header and all the 2- or 4-byte substream headers. */
282 // Only check when this isn't a sync frame - syncs have a checksum.
285 for (i = -1; i < mp->num_substreams; i++) {
286 parity_bits ^= buf[p++];
287 parity_bits ^= buf[p++];
289 if (i < 0 || buf[p-2] & 0x80) {
290 parity_bits ^= buf[p++];
291 parity_bits ^= buf[p++];
295 if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
296 av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
303 init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
304 if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
307 avctx->bits_per_raw_sample = mh.group1_bits;
308 if (avctx->bits_per_raw_sample > 16)
309 avctx->sample_fmt = AV_SAMPLE_FMT_S32;
311 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
312 avctx->sample_rate = mh.group1_samplerate;
313 avctx->frame_size = mh.access_unit_size;
315 if (mh.stream_type == 0xbb) {
317 avctx->channels = mlp_channels[mh.channels_mlp];
318 avctx->channel_layout = mlp_layout[mh.channels_mlp];
319 } else { /* mh.stream_type == 0xba */
321 if (mh.channels_thd_stream2) {
322 avctx->channels = truehd_channels(mh.channels_thd_stream2);
323 avctx->channel_layout = truehd_layout(mh.channels_thd_stream2);
325 avctx->channels = truehd_channels(mh.channels_thd_stream1);
326 avctx->channel_layout = truehd_layout(mh.channels_thd_stream1);
330 if (!mh.is_vbr) /* Stream is CBR */
331 avctx->bit_rate = mh.peak_bitrate;
333 mp->num_substreams = mh.num_substreams;
337 *poutbuf_size = buf_size;
346 AVCodecParser ff_mlp_parser = {
347 { CODEC_ID_MLP, CODEC_ID_TRUEHD },
348 sizeof(MLPParseContext),