3 * Copyright (c) 2009 Justin Ruggles
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
22 #include "libavutil/channel_layout.h"
23 #include "libavutil/crc.h"
24 #include "libavutil/log.h"
26 #include "bitstream.h"
27 #include "bytestream.h"
31 static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
33 static const uint64_t flac_channel_layouts[8] = {
36 AV_CH_LAYOUT_SURROUND,
44 static int64_t get_utf8(BitstreamContext *bc)
47 GET_UTF8(val, bitstream_read(bc, 8), return -1;)
51 int ff_flac_decode_frame_header(AVCodecContext *avctx, BitstreamContext *bc,
52 FLACFrameInfo *fi, int log_level_offset)
54 int bs_code, sr_code, bps_code;
57 if ((bitstream_read(bc, 15) & 0x7FFF) != 0x7FFC) {
58 av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n");
59 return AVERROR_INVALIDDATA;
62 /* variable block size stream code */
63 fi->is_var_size = bitstream_read_bit(bc);
65 /* block size and sample rate codes */
66 bs_code = bitstream_read(bc, 4);
67 sr_code = bitstream_read(bc, 4);
69 /* channels and decorrelation */
70 fi->ch_mode = bitstream_read(bc, 4);
71 if (fi->ch_mode < FLAC_MAX_CHANNELS) {
72 fi->channels = fi->ch_mode + 1;
73 fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
74 } else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
76 fi->ch_mode -= FLAC_MAX_CHANNELS - 1;
78 av_log(avctx, AV_LOG_ERROR + log_level_offset,
79 "invalid channel mode: %d\n", fi->ch_mode);
80 return AVERROR_INVALIDDATA;
84 bps_code = bitstream_read(bc, 3);
85 if (bps_code == 3 || bps_code == 7) {
86 av_log(avctx, AV_LOG_ERROR + log_level_offset,
87 "invalid sample size code (%d)\n",
89 return AVERROR_INVALIDDATA;
91 fi->bps = sample_size_table[bps_code];
94 if (bitstream_read_bit(bc)) {
95 av_log(avctx, AV_LOG_ERROR + log_level_offset,
96 "broken stream, invalid padding\n");
97 return AVERROR_INVALIDDATA;
100 /* sample or frame count */
101 fi->frame_or_sample_num = get_utf8(bc);
102 if (fi->frame_or_sample_num < 0) {
103 av_log(avctx, AV_LOG_ERROR + log_level_offset,
104 "sample/frame number invalid; utf8 fscked\n");
105 return AVERROR_INVALIDDATA;
110 av_log(avctx, AV_LOG_ERROR + log_level_offset,
111 "reserved blocksize code: 0\n");
112 return AVERROR_INVALIDDATA;
113 } else if (bs_code == 6) {
114 fi->blocksize = bitstream_read(bc, 8) + 1;
115 } else if (bs_code == 7) {
116 fi->blocksize = bitstream_read(bc, 16) + 1;
118 fi->blocksize = ff_flac_blocksize_table[bs_code];
123 fi->samplerate = ff_flac_sample_rate_table[sr_code];
124 } else if (sr_code == 12) {
125 fi->samplerate = bitstream_read(bc, 8) * 1000;
126 } else if (sr_code == 13) {
127 fi->samplerate = bitstream_read(bc, 16);
128 } else if (sr_code == 14) {
129 fi->samplerate = bitstream_read(bc, 16) * 10;
131 av_log(avctx, AV_LOG_ERROR + log_level_offset,
132 "illegal sample rate code %d\n",
134 return AVERROR_INVALIDDATA;
137 /* header CRC-8 check */
138 bitstream_skip(bc, 8);
139 if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, bc->buffer,
140 bitstream_tell(bc) / 8)) {
141 av_log(avctx, AV_LOG_ERROR + log_level_offset,
142 "header crc mismatch\n");
143 return AVERROR_INVALIDDATA;
149 int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
151 /* Technically, there is no limit to FLAC frame size, but an encoder
152 should not write a frame that is larger than if verbatim encoding mode
157 count = 16; /* frame header */
158 count += ch * ((7+bps+7)/8); /* subframe headers */
160 /* for stereo, need to account for using decorrelation */
161 count += (( 2*bps+1) * blocksize + 7) / 8;
163 count += ( ch*bps * blocksize + 7) / 8;
165 count += 2; /* frame footer */
170 int ff_flac_is_extradata_valid(AVCodecContext *avctx,
171 enum FLACExtradataFormat *format,
172 uint8_t **streaminfo_start)
174 if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
175 av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
178 if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
179 /* extradata contains STREAMINFO only */
180 if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
181 av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
182 FLAC_STREAMINFO_SIZE-avctx->extradata_size);
184 *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
185 *streaminfo_start = avctx->extradata;
187 if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
188 av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
191 *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
192 *streaminfo_start = &avctx->extradata[8];
197 void ff_flac_set_channel_layout(AVCodecContext *avctx)
199 if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts))
200 avctx->channel_layout = flac_channel_layouts[avctx->channels - 1];
202 avctx->channel_layout = 0;
205 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
206 const uint8_t *buffer)
209 bitstream_init8(&bc, buffer, FLAC_STREAMINFO_SIZE);
211 bitstream_skip(&bc, 16); /* skip min blocksize */
212 s->max_blocksize = bitstream_read(&bc, 16);
213 if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) {
214 av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
216 s->max_blocksize = 16;
219 bitstream_skip(&bc, 24); /* skip min frame size */
220 s->max_framesize = bitstream_read(&bc, 24);
221 s->samplerate = bitstream_read(&bc, 20);
222 s->channels = bitstream_read(&bc, 3) + 1;
223 s->bps = bitstream_read(&bc, 5) + 1;
225 avctx->channels = s->channels;
226 avctx->sample_rate = s->samplerate;
227 avctx->bits_per_raw_sample = s->bps;
229 if (!avctx->channel_layout ||
230 av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels)
231 ff_flac_set_channel_layout(avctx);
233 s->samples = bitstream_read(&bc, 32) << 4;
234 s->samples |= bitstream_read(&bc, 4);
236 bitstream_skip(&bc, 64); /* md5 sum */
237 bitstream_skip(&bc, 64); /* md5 sum */
240 #if LIBAVCODEC_VERSION_MAJOR < 57
241 void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
242 const uint8_t *buffer)
244 ff_flac_parse_streaminfo(avctx, s, buffer);
247 int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
248 enum FLACExtradataFormat *format,
249 uint8_t **streaminfo_start)
251 return ff_flac_is_extradata_valid(avctx, format, streaminfo_start);