3 * Copyright (c) 2009 Justin Ruggles
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
22 #include "libavutil/channel_layout.h"
23 #include "libavutil/crc.h"
24 #include "libavutil/log.h"
25 #include "bytestream.h"
30 static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
32 static const int64_t flac_channel_layouts[6] = {
35 AV_CH_LAYOUT_SURROUND,
41 static int64_t get_utf8(GetBitContext *gb)
44 GET_UTF8(val, get_bits(gb, 8), return -1;)
48 int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
49 FLACFrameInfo *fi, int log_level_offset)
51 int bs_code, sr_code, bps_code;
54 if ((get_bits(gb, 15) & 0x7FFF) != 0x7FFC) {
55 av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n");
59 /* variable block size stream code */
60 fi->is_var_size = get_bits1(gb);
62 /* block size and sample rate codes */
63 bs_code = get_bits(gb, 4);
64 sr_code = get_bits(gb, 4);
66 /* channels and decorrelation */
67 fi->ch_mode = get_bits(gb, 4);
68 if (fi->ch_mode < FLAC_MAX_CHANNELS) {
69 fi->channels = fi->ch_mode + 1;
70 fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
71 } else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
73 fi->ch_mode -= FLAC_MAX_CHANNELS - 1;
75 av_log(avctx, AV_LOG_ERROR + log_level_offset,
76 "invalid channel mode: %d\n", fi->ch_mode);
81 bps_code = get_bits(gb, 3);
82 if (bps_code == 3 || bps_code == 7) {
83 av_log(avctx, AV_LOG_ERROR + log_level_offset,
84 "invalid sample size code (%d)\n",
88 fi->bps = sample_size_table[bps_code];
92 av_log(avctx, AV_LOG_ERROR + log_level_offset,
93 "broken stream, invalid padding\n");
97 /* sample or frame count */
98 fi->frame_or_sample_num = get_utf8(gb);
99 if (fi->frame_or_sample_num < 0) {
100 av_log(avctx, AV_LOG_ERROR + log_level_offset,
101 "sample/frame number invalid; utf8 fscked\n");
107 av_log(avctx, AV_LOG_ERROR + log_level_offset,
108 "reserved blocksize code: 0\n");
110 } else if (bs_code == 6) {
111 fi->blocksize = get_bits(gb, 8) + 1;
112 } else if (bs_code == 7) {
113 fi->blocksize = get_bits(gb, 16) + 1;
115 fi->blocksize = ff_flac_blocksize_table[bs_code];
120 fi->samplerate = ff_flac_sample_rate_table[sr_code];
121 } else if (sr_code == 12) {
122 fi->samplerate = get_bits(gb, 8) * 1000;
123 } else if (sr_code == 13) {
124 fi->samplerate = get_bits(gb, 16);
125 } else if (sr_code == 14) {
126 fi->samplerate = get_bits(gb, 16) * 10;
128 av_log(avctx, AV_LOG_ERROR + log_level_offset,
129 "illegal sample rate code %d\n",
134 /* header CRC-8 check */
136 if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
137 get_bits_count(gb)/8)) {
138 av_log(avctx, AV_LOG_ERROR + log_level_offset,
139 "header crc mismatch\n");
146 int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
148 /* Technically, there is no limit to FLAC frame size, but an encoder
149 should not write a frame that is larger than if verbatim encoding mode
154 count = 16; /* frame header */
155 count += ch * ((7+bps+7)/8); /* subframe headers */
157 /* for stereo, need to account for using decorrelation */
158 count += (( 2*bps+1) * blocksize + 7) / 8;
160 count += ( ch*bps * blocksize + 7) / 8;
162 count += 2; /* frame footer */
167 int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
168 enum FLACExtradataFormat *format,
169 uint8_t **streaminfo_start)
171 if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
172 av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
175 if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
176 /* extradata contains STREAMINFO only */
177 if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
178 av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
179 FLAC_STREAMINFO_SIZE-avctx->extradata_size);
181 *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
182 *streaminfo_start = avctx->extradata;
184 if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
185 av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
188 *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
189 *streaminfo_start = &avctx->extradata[8];
194 void ff_flac_set_channel_layout(AVCodecContext *avctx)
196 if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts))
197 avctx->channel_layout = flac_channel_layouts[avctx->channels - 1];
199 avctx->channel_layout = 0;
202 void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
203 const uint8_t *buffer)
206 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
208 skip_bits(&gb, 16); /* skip min blocksize */
209 s->max_blocksize = get_bits(&gb, 16);
210 if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) {
211 av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
213 s->max_blocksize = 16;
216 skip_bits(&gb, 24); /* skip min frame size */
217 s->max_framesize = get_bits_long(&gb, 24);
219 s->samplerate = get_bits_long(&gb, 20);
220 s->channels = get_bits(&gb, 3) + 1;
221 s->bps = get_bits(&gb, 5) + 1;
223 avctx->channels = s->channels;
224 avctx->sample_rate = s->samplerate;
225 avctx->bits_per_raw_sample = s->bps;
226 ff_flac_set_channel_layout(avctx);
228 s->samples = get_bits_longlong(&gb, 36);
230 skip_bits_long(&gb, 64); /* md5 sum */
231 skip_bits_long(&gb, 64); /* md5 sum */
234 void avpriv_flac_parse_block_header(const uint8_t *block_header,
235 int *last, int *type, int *size)
237 int tmp = bytestream_get_byte(&block_header);
243 *size = bytestream_get_be24(&block_header);