diff options
author | Justin Ruggles <justin.ruggles@gmail.com> | 2009-03-24 04:17:55 +0300 |
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committer | Justin Ruggles <justin.ruggles@gmail.com> | 2009-03-24 04:17:55 +0300 |
commit | cd98a0302498521917b52386cc60cdaaf610f558 (patch) | |
tree | ff4d3777d847d52e1a1f38d336a5ba29bbcdc939 /libavcodec/flacdec.c | |
parent | 77544e5b910d4497c4de6755c6cd5cecf1634361 (diff) |
flacdec: split frame header decoding and validation into a separate
function
Originally committed as revision 18175 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/flacdec.c')
-rw-r--r-- | libavcodec/flacdec.c | 93 |
1 files changed, 56 insertions, 37 deletions
diff --git a/libavcodec/flacdec.c b/libavcodec/flacdec.c index da23ffb521..a2ab8721c8 100644 --- a/libavcodec/flacdec.c +++ b/libavcodec/flacdec.c @@ -480,75 +480,80 @@ static inline int decode_subframe(FLACContext *s, int channel) return 0; } -static int decode_frame(FLACContext *s) +/** + * Validate and decode a frame header. + * @param avctx AVCodecContext to use as av_log() context + * @param gb GetBitContext from which to read frame header + * @param[out] fi frame information + */ +static int decode_frame_header(AVCodecContext *avctx, GetBitContext *gb, + FLACFrameInfo *fi) { - int bs_code, sr_code, bps_code, i; - int ch_mode, bps, blocksize, samplerate, channels; - GetBitContext *gb = &s->gb; + int bs_code, sr_code, bps_code; /* frame sync code */ - skip_bits(&s->gb, 16); + skip_bits(gb, 16); /* block size and sample rate codes */ bs_code = get_bits(gb, 4); sr_code = get_bits(gb, 4); /* channels and decorrelation */ - ch_mode = get_bits(gb, 4); - if (ch_mode < FLAC_MAX_CHANNELS) { - channels = ch_mode + 1; - ch_mode = FLAC_CHMODE_INDEPENDENT; - } else if (ch_mode <= FLAC_CHMODE_MID_SIDE) { - channels = 2; + fi->ch_mode = get_bits(gb, 4); + if (fi->ch_mode < FLAC_MAX_CHANNELS) { + fi->channels = fi->ch_mode + 1; + fi->ch_mode = FLAC_CHMODE_INDEPENDENT; + } else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) { + fi->channels = 2; } else { - av_log(s->avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", ch_mode); + av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode); return -1; } /* bits per sample */ bps_code = get_bits(gb, 3); if (bps_code == 3 || bps_code == 7) { - av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", + av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", bps_code); return -1; } - bps = sample_size_table[bps_code]; + fi->bps = sample_size_table[bps_code]; /* reserved bit */ if (get_bits1(gb)) { - av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n"); + av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n"); return -1; } /* sample or frame count */ if (get_utf8(gb) < 0) { - av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n"); + av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n"); return -1; } /* blocksize */ if (bs_code == 0) { - av_log(s->avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n"); + av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n"); return -1; } else if (bs_code == 6) { - blocksize = get_bits(gb, 8) + 1; + fi->blocksize = get_bits(gb, 8) + 1; } else if (bs_code == 7) { - blocksize = get_bits(gb, 16) + 1; + fi->blocksize = get_bits(gb, 16) + 1; } else { - blocksize = ff_flac_blocksize_table[bs_code]; + fi->blocksize = ff_flac_blocksize_table[bs_code]; } /* sample rate */ if (sr_code < 12) { - samplerate = ff_flac_sample_rate_table[sr_code]; + fi->samplerate = ff_flac_sample_rate_table[sr_code]; } else if (sr_code == 12) { - samplerate = get_bits(gb, 8) * 1000; + fi->samplerate = get_bits(gb, 8) * 1000; } else if (sr_code == 13) { - samplerate = get_bits(gb, 16); + fi->samplerate = get_bits(gb, 16); } else if (sr_code == 14) { - samplerate = get_bits(gb, 16) * 10; + fi->samplerate = get_bits(gb, 16) * 10; } else { - av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", + av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sr_code); return -1; } @@ -557,18 +562,32 @@ static int decode_frame(FLACContext *s) skip_bits(gb, 8); if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer, get_bits_count(gb)/8)) { - av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch\n"); + av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n"); + return -1; + } + + return 0; +} + +static int decode_frame(FLACContext *s) +{ + int i; + GetBitContext *gb = &s->gb; + FLACFrameInfo fi; + + if (decode_frame_header(s->avctx, gb, &fi)) { + av_log(s->avctx, AV_LOG_ERROR, "invalid frame header\n"); return -1; } - if (channels != s->channels) { + if (fi.channels != s->channels) { av_log(s->avctx, AV_LOG_ERROR, "switching channel layout mid-stream " "is not supported\n"); return -1; } - s->ch_mode = ch_mode; + s->ch_mode = fi.ch_mode; - if (bps && bps != s->bps) { + if (fi.bps && fi.bps != s->bps) { av_log(s->avctx, AV_LOG_ERROR, "switching bps mid-stream is not " "supported\n"); return -1; @@ -583,20 +602,20 @@ static int decode_frame(FLACContext *s) s->is32 = 0; } - if (blocksize > s->max_blocksize) { - av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, + if (fi.blocksize > s->max_blocksize) { + av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", fi.blocksize, s->max_blocksize); return -1; } - s->blocksize = blocksize; + s->blocksize = fi.blocksize; - if (samplerate == 0) { - samplerate = s->samplerate; - } else if (samplerate != s->samplerate) { + if (fi.samplerate == 0) { + fi.samplerate = s->samplerate; + } else if (fi.samplerate != s->samplerate) { av_log(s->avctx, AV_LOG_WARNING, "sample rate changed from %d to %d\n", - s->samplerate, samplerate); + s->samplerate, fi.samplerate); } - s->samplerate = s->avctx->sample_rate = samplerate; + s->samplerate = s->avctx->sample_rate = fi.samplerate; // dump_headers(s->avctx, (FLACStreaminfo *)s); |