From cd98a0302498521917b52386cc60cdaaf610f558 Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Tue, 24 Mar 2009 01:17:55 +0000 Subject: [PATCH] flacdec: split frame header decoding and validation into a separate function Originally committed as revision 18175 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/flac.h | 15 +++++-- libavcodec/flacdec.c | 93 ++++++++++++++++++++++++++------------------ 2 files changed, 68 insertions(+), 40 deletions(-) diff --git a/libavcodec/flac.h b/libavcodec/flac.h index 7ac2897404..25494ed667 100644 --- a/libavcodec/flac.h +++ b/libavcodec/flac.h @@ -57,22 +57,31 @@ enum FLACExtradataFormat { FLAC_EXTRADATA_FORMAT_FULL_HEADER = 1 }; +#define FLACCOMMONINFO \ + int samplerate; /**< sample rate */\ + int channels; /**< number of channels */\ + int bps; /**< bits-per-sample */\ + /** * Data needed from the Streaminfo header for use by the raw FLAC demuxer * and/or the FLAC decoder. */ #define FLACSTREAMINFO \ + FLACCOMMONINFO \ int max_blocksize; /**< maximum block size, in samples */\ int max_framesize; /**< maximum frame size, in bytes */\ - int samplerate; /**< sample rate */\ - int channels; /**< number of channels */\ - int bps; /**< bits-per-sample */\ int64_t samples; /**< total number of samples */\ typedef struct FLACStreaminfo { FLACSTREAMINFO } FLACStreaminfo; +typedef struct FLACFrameInfo { + FLACCOMMONINFO + int blocksize; /**< block size of the frame */ + int ch_mode; /**< channel decorrelation mode */ +} FLACFrameInfo; + /** * Parse the Streaminfo metadata block * @param[out] avctx codec context to set basic stream parameters 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);