从ffmpeg上移植下来的flac解码函数并在PC上测试通过

/* * FLAC (Free Lossless Audio Codec) decoder * @author Alex Beregszaszi * * For more information on the FLAC format, visit: * http://flac.sourceforge.net/ * * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed * through, starting from the initial 'fLaC' signature; or by passing the * 34-byte streaminfo structure through avctx->extradata[_size] followed * by data starting with the 0xFFF8 marker. */ #include <limits.h> #include <stdio.h> #include <assert.h> #include "flacdec.h" #define AV_RB8(x) (((const unsigned char*)(x))[0]) #define AV_RB32(x) \ (((unsigned int)((const unsigned char*)(x))[0] << 24) | \ (((const unsigned char*)(x))[1] << 16) | \ (((const unsigned char*)(x))[2] << 8) | \ ((const unsigned char*)(x))[3]) #define AV_RB24(x) \ ((((const unsigned char*)(x))[0] << 16) | \ (((const unsigned char*)(x))[1] << 8) | \ ((const unsigned char*)(x))[2]) #define AV_RL32(x) \ (((unsigned int)((const unsigned char*)(x))[3] << 24) | \ (((const unsigned char*)(x))[2] << 16) | \ (((const unsigned char*)(x))[1] << 8) | \ ((const unsigned char*)(x))[0]) static void allocate_buffers(FLACContext *s); static const int sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 }; const int ff_flac_sample_rate_table[16] = { 0, 88200, 176400, 192000, 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000, 0, 0, 0, 0 }; const int ff_flac_blocksize_table[16] = { 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0, 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7 }; static const unsigned char table_crc8[256] = { 0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d, 0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65, 0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d, 0xe0, 0xe7, 0xee, 0xe9, 0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd, 0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1, 0xb4, 0xb3, 0xba, 0xbd, 0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2, 0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea, 0xb7, 0xb0, 0xb9, 0xbe, 0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a, 0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0d, 0x0a, 0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42, 0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a, 0x89, 0x8e, 0x87, 0x80, 0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4, 0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8, 0xdd, 0xda, 0xd3, 0xd4, 0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c, 0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44, 0x19, 0x1e, 0x17, 0x10, 0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34, 0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f, 0x6a, 0x6d, 0x64, 0x63, 0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b, 0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13, 0xae, 0xa9, 0xa0, 0xa7, 0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83, 0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef, 0xfa, 0xfd, 0xf4, 0xf3 }; int my_bui_clz(unsigned int a) { int i; unsigned int tmp_index = 1 << 31; if(a == 0) return 31; for(i=0;i<32;i++) { if((a & tmp_index)==tmp_index) return i; else tmp_index = tmp_index >> 1; } } static long long int get_utf8(GetBitContext *gb) { long long int val; GET_UTF8(val, get_bits(gb, 8), return -1;) return val; } static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s) { printf("Max Blocksize: %d\n", s->max_blocksize); printf("Max Framesize: %d\n", s->max_framesize); printf("Samplerate: %d\n", s->samplerate); printf("Channels: %d\n", s->channels); printf("Bits: %d\n", s->bps); } void ff_flac_parse_streaminfo(AVCodecContext *avctx, FLACStreaminfo *s,const unsigned char *buffer) { GetBitContext gb; init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8); skip_bits(&gb, 16); /* skip min blocksize */ s->max_blocksize = get_bits(&gb, 16); if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) { printf("AV_LOG_WARNING : invalid max blocksize: %d\n",s->max_blocksize); s->max_blocksize = 16; } skip_bits(&gb, 24); /* skip min frame size */ s->max_framesize = get_bits_long(&gb, 24); s->samplerate = get_bits_long(&gb, 20); s->channels = get_bits(&gb, 3) + 1; s->bps = get_bits(&gb, 5) + 1; avctx->channels = s->channels; avctx->sample_rate = s->samplerate; avctx->bits_per_raw_sample = s->bps; s->samples = get_bits_long(&gb, 32) << 4; s->samples |= get_bits(&gb, 4); skip_bits_long(&gb, 64); /* md5 sum */ skip_bits_long(&gb, 64); /* md5 sum */ dump_headers(avctx, s); } int ff_flac_get_max_frame_size(int blocksize, int ch, int bps) { /* Technically, there is no limit to FLAC frame size, but an encoder should not write a frame that is larger than if verbatim encoding mode were to be used. */ int count; count = 16; /* frame header */ count += ch * ((7+bps+7)/8); /* subframe headers */ if (ch == 2) { /* for stereo, need to account for using decorrelation */ count += (( 2*bps+1) * blocksize + 7) / 8; } else { count += ( ch*bps * blocksize + 7) / 8; } count += 2; /* frame footer */ return count; } int ff_flac_is_extradata_valid(AVCodecContext *avctx, enum FLACExtradataFormat *format, unsigned char **streaminfo_start) { if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) { printf("extradata NULL or too small.\n"); return 0; } if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) { /** extradata contains STREAMINFO only */ if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) { printf("extradata contains bytes too many.\n"); } *format = FLAC_EXTRADATA_FORMAT_STREAMINFO; *streaminfo_start = avctx->extradata; } else { if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) { printf("extradata too small.\n"); return 0; } *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER; *streaminfo_start = &avctx->extradata[8]; } return 1; } int flac_decode_init(AVCodecContext *avctx) { enum FLACExtradataFormat format; unsigned char *streaminfo; FLACContext *s = avctx->priv_data; s->avctx = avctx; avctx->sample_fmt = AV_SAMPLE_FMT_S16; /** for now, the raw FLAC header is allowed to be passed to the decoder as frame data instead of extradata. */ if (!avctx->extradata) return 0; printf("it is init\n"); if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo)) return -1; /** initialize based on the demuxer-supplied streamdata header */ ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, streaminfo); if (s->bps > 16) avctx->sample_fmt = AV_SAMPLE_FMT_S32; else avctx->sample_fmt = AV_SAMPLE_FMT_S16; allocate_buffers(s); s->got_streaminfo = 1; return 0; } static void allocate_buffers(FLACContext *s) { int i; assert(s->max_blocksize); for (i = 0; i < s->channels; i++) { s->decoded[i] = malloc(sizeof(int)*s->max_blocksize); } } static unsigned int bytestream_get_byte(const unsigned char **b) { (*b) += 1; return AV_RB8(*b - 1); } static unsigned int bytestream_get_be24(const unsigned char **b) { (*b) += 3; return AV_RB24(*b - 3); } void ff_flac_parse_block_header(const unsigned char *block_header, int *last, int *type, int *size) { int tm