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author | Michael Niedermayer <michaelni@gmx.at> | 2006-03-06 14:53:13 +0000 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2006-03-06 14:53:13 +0000 |
commit | e027d0a81ee012b3876a616f49dd84be66ff34f5 (patch) | |
tree | 82513a2169f724332c334026bfd74477af9c478a /libavcodec/ac3enc.c | |
parent | 43a80ccee52bd478cbc5b575f9b4424de352138d (diff) | |
download | ffmpeg-streaming-e027d0a81ee012b3876a616f49dd84be66ff34f5.zip ffmpeg-streaming-e027d0a81ee012b3876a616f49dd84be66ff34f5.tar.gz |
switch ac3enc to av_crc
Originally committed as revision 5116 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/ac3enc.c')
-rw-r--r-- | libavcodec/ac3enc.c | 35 |
1 files changed, 3 insertions, 32 deletions
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c index 0f9badf..5084394 100644 --- a/libavcodec/ac3enc.c +++ b/libavcodec/ac3enc.c @@ -25,6 +25,7 @@ //#define DEBUG_BITALLOC #include "avcodec.h" #include "bitstream.h" +#include "crc.h" #include "ac3.h" typedef struct AC3EncodeContext { @@ -66,7 +67,6 @@ typedef struct AC3EncodeContext { #define EXP_DIFF_THRESHOLD 1000 static void fft_init(int ln); -static void ac3_crc_init(void); static inline int16_t fix15(float a) { @@ -886,8 +886,6 @@ static int AC3_encode_init(AVCodecContext *avctx) xsin1[i] = fix15(-sin(alpha)); } - ac3_crc_init(); - avctx->coded_frame= avcodec_alloc_frame(); avctx->coded_frame->key_frame= 1; @@ -1236,35 +1234,8 @@ static void output_audio_block(AC3EncodeContext *s, } } -/* compute the ac3 crc */ - #define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16)) -static void ac3_crc_init(void) -{ - unsigned int c, n, k; - - for(n=0;n<256;n++) { - c = n << 8; - for (k = 0; k < 8; k++) { - if (c & (1 << 15)) - c = ((c << 1) & 0xffff) ^ (CRC16_POLY & 0xffff); - else - c = c << 1; - } - crc_table[n] = c; - } -} - -static unsigned int ac3_crc(uint8_t *data, int n, unsigned int crc) -{ - int i; - for(i=0;i<n;i++) { - crc = (crc_table[data[i] ^ (crc >> 8)] ^ (crc << 8)) & 0xffff; - } - return crc; -} - static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly) { unsigned int c; @@ -1342,14 +1313,14 @@ static int output_frame_end(AC3EncodeContext *s) /* Now we must compute both crcs : this is not so easy for crc1 because it is at the beginning of the data... */ frame_size_58 = (frame_size >> 1) + (frame_size >> 3); - crc1 = ac3_crc(frame + 4, (2 * frame_size_58) - 4, 0); + crc1 = bswap_16(av_crc(av_crc8005, 0, frame + 4, 2 * frame_size_58 - 4)); /* XXX: could precompute crc_inv */ crc_inv = pow_poly((CRC16_POLY >> 1), (16 * frame_size_58) - 16, CRC16_POLY); crc1 = mul_poly(crc_inv, crc1, CRC16_POLY); frame[2] = crc1 >> 8; frame[3] = crc1; - crc2 = ac3_crc(frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2, 0); + crc2 = bswap_16(av_crc(av_crc8005, 0, frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2)); frame[2*frame_size - 2] = crc2 >> 8; frame[2*frame_size - 1] = crc2; |