Move decode_frame_header() from flacdec.c to flac.c/h to share with the
forthcoming FLAC parser. Patch by Michael Chinen [mchinen at gmail] Originally committed as revision 25909 to svn://svn.ffmpeg.org/ffmpeg/trunk
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@ -19,7 +19,101 @@
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/crc.h"
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#include "flac.h"
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#include "flacdata.h"
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static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
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static int64_t get_utf8(GetBitContext *gb)
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{
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int64_t val;
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GET_UTF8(val, get_bits(gb, 8), return -1;)
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return val;
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}
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int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
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FLACFrameInfo *fi)
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{
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int bs_code, sr_code, bps_code;
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/* frame sync code */
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skip_bits(gb, 16);
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/* block size and sample rate codes */
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bs_code = get_bits(gb, 4);
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sr_code = get_bits(gb, 4);
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/* channels and decorrelation */
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fi->ch_mode = get_bits(gb, 4);
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if (fi->ch_mode < FLAC_MAX_CHANNELS) {
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fi->channels = fi->ch_mode + 1;
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fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
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} else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) {
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fi->channels = 2;
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} else {
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av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode);
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return -1;
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}
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/* bits per sample */
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bps_code = get_bits(gb, 3);
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if (bps_code == 3 || bps_code == 7) {
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av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
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bps_code);
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return -1;
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}
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fi->bps = sample_size_table[bps_code];
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/* reserved bit */
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if (get_bits1(gb)) {
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av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
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return -1;
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}
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/* sample or frame count */
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if (get_utf8(gb) < 0) {
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av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n");
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return -1;
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}
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/* blocksize */
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if (bs_code == 0) {
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av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
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return -1;
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} else if (bs_code == 6) {
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fi->blocksize = get_bits(gb, 8) + 1;
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} else if (bs_code == 7) {
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fi->blocksize = get_bits(gb, 16) + 1;
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} else {
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fi->blocksize = ff_flac_blocksize_table[bs_code];
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}
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/* sample rate */
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if (sr_code < 12) {
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fi->samplerate = ff_flac_sample_rate_table[sr_code];
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} else if (sr_code == 12) {
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fi->samplerate = get_bits(gb, 8) * 1000;
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} else if (sr_code == 13) {
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fi->samplerate = get_bits(gb, 16);
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} else if (sr_code == 14) {
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fi->samplerate = get_bits(gb, 16) * 10;
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} else {
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av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
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sr_code);
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return -1;
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}
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/* header CRC-8 check */
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skip_bits(gb, 8);
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if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
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get_bits_count(gb)/8)) {
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av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n");
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return -1;
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}
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return 0;
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}
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int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
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{
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@ -28,6 +28,7 @@
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#define AVCODEC_FLAC_H
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#include "avcodec.h"
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#include "get_bits.h"
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#define FLAC_STREAMINFO_SIZE 34
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#define FLAC_MAX_CHANNELS 8
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@ -120,4 +121,13 @@ void ff_flac_parse_block_header(const uint8_t *block_header,
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*/
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int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
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/**
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* Validate and decode a frame header.
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* @param avctx AVCodecContext to use as av_log() context
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* @param gb GetBitContext from which to read frame header
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* @param[out] fi frame information
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* @return non-zero on error, 0 if ok
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*/
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int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
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FLACFrameInfo *fi);
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#endif /* AVCODEC_FLAC_H */
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@ -67,16 +67,6 @@ typedef struct FLACContext {
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unsigned int allocated_bitstream_size;
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} FLACContext;
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static const int sample_size_table[] =
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{ 0, 8, 12, 0, 16, 20, 24, 0 };
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static int64_t get_utf8(GetBitContext *gb)
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{
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int64_t val;
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GET_UTF8(val, get_bits(gb, 8), return -1;)
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return val;
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}
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static void allocate_buffers(FLACContext *s);
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int ff_flac_is_extradata_valid(AVCodecContext *avctx,
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@ -480,103 +470,13 @@ static inline int decode_subframe(FLACContext *s, int channel)
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return 0;
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}
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/**
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* Validate and decode a frame header.
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* @param avctx AVCodecContext to use as av_log() context
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* @param gb GetBitContext from which to read frame header
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* @param[out] fi frame information
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* @return non-zero on error, 0 if ok
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*/
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static int decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
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FLACFrameInfo *fi)
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{
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int bs_code, sr_code, bps_code;
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/* frame sync code */
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skip_bits(gb, 16);
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/* block size and sample rate codes */
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bs_code = get_bits(gb, 4);
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sr_code = get_bits(gb, 4);
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/* channels and decorrelation */
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fi->ch_mode = get_bits(gb, 4);
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if (fi->ch_mode < FLAC_MAX_CHANNELS) {
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fi->channels = fi->ch_mode + 1;
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fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
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} else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) {
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fi->channels = 2;
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} else {
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av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode);
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return -1;
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}
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/* bits per sample */
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bps_code = get_bits(gb, 3);
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if (bps_code == 3 || bps_code == 7) {
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av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
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bps_code);
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return -1;
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}
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fi->bps = sample_size_table[bps_code];
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/* reserved bit */
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if (get_bits1(gb)) {
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av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
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return -1;
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}
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/* sample or frame count */
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if (get_utf8(gb) < 0) {
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av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n");
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return -1;
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}
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/* blocksize */
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if (bs_code == 0) {
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av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
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return -1;
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} else if (bs_code == 6) {
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fi->blocksize = get_bits(gb, 8) + 1;
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} else if (bs_code == 7) {
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fi->blocksize = get_bits(gb, 16) + 1;
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} else {
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fi->blocksize = ff_flac_blocksize_table[bs_code];
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}
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/* sample rate */
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if (sr_code < 12) {
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fi->samplerate = ff_flac_sample_rate_table[sr_code];
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} else if (sr_code == 12) {
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fi->samplerate = get_bits(gb, 8) * 1000;
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} else if (sr_code == 13) {
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fi->samplerate = get_bits(gb, 16);
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} else if (sr_code == 14) {
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fi->samplerate = get_bits(gb, 16) * 10;
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} else {
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av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
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sr_code);
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return -1;
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}
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/* header CRC-8 check */
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skip_bits(gb, 8);
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if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
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get_bits_count(gb)/8)) {
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av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n");
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return -1;
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}
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return 0;
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}
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static int decode_frame(FLACContext *s)
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{
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int i;
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GetBitContext *gb = &s->gb;
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FLACFrameInfo fi;
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if (decode_frame_header(s->avctx, gb, &fi)) {
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if (ff_flac_decode_frame_header(s->avctx, gb, &fi)) {
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av_log(s->avctx, AV_LOG_ERROR, "invalid frame header\n");
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return -1;
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}
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