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| author | Michael Niedermayer <michaelni@gmx.at> | 2007-04-07 22:04:33 +0000 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2007-04-07 22:04:33 +0000 |
| commit | 949ed6bb30c1bc08df38ebb7c0f015a9c045fd32 (patch) | |
| tree | 959e292e33622084048f14de2fcec2ef5e9c0f1f | |
| parent | 8e952e4d2372c743b35fae4060f13f2e128cad96 (diff) | |
| download | ffmpeg-949ed6bb30c1bc08df38ebb7c0f015a9c045fd32.tar.gz | |
use bytestream reader instead of bitstream for THP
5% smaller adpcm.o
20% faster
Originally committed as revision 8657 to svn://svn.ffmpeg.org/ffmpeg/trunk
| -rw-r--r-- | libavcodec/adpcm.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c index eafb0363db..e03a4b4879 100644 --- a/libavcodec/adpcm.c +++ b/libavcodec/adpcm.c @@ -20,6 +20,7 @@ */ #include "avcodec.h" #include "bitstream.h" +#include "bytestream.h" /** * @file adpcm.c @@ -1317,7 +1318,6 @@ static int adpcm_decode_frame(AVCodecContext *avctx, break; case CODEC_ID_ADPCM_THP: { - GetBitContext gb; int table[2][16]; unsigned int samplecnt; int prev[2][2]; @@ -1328,18 +1328,15 @@ static int adpcm_decode_frame(AVCodecContext *avctx, return -1; } - init_get_bits(&gb, src, buf_size * 8); - src += buf_size; - - get_bits_long(&gb, 32); /* Channel size */ - samplecnt = get_bits_long(&gb, 32); + src+=4; + samplecnt = bytestream_get_be32(&src); for (i = 0; i < 32; i++) - table[0][i] = get_sbits(&gb, 16); + table[0][i] = (int16_t)bytestream_get_be16(&src); /* Initialize the previous sample. */ for (i = 0; i < 4; i++) - prev[0][i] = get_sbits(&gb, 16); + prev[0][i] = (int16_t)bytestream_get_be16(&src); if (samplecnt >= (samples_end - samples) / (st + 1)) { av_log(avctx, AV_LOG_ERROR, "allocated output buffer is too small\n"); @@ -1351,17 +1348,19 @@ static int adpcm_decode_frame(AVCodecContext *avctx, /* Read in every sample for this channel. */ for (i = 0; i < samplecnt / 14; i++) { - int index = get_bits (&gb, 4) & 7; - unsigned int exp = get_bits (&gb, 4); + int index = (*src >> 4) & 7; + unsigned int exp = 28 - (*src++ & 15); int factor1 = table[ch][index * 2]; int factor2 = table[ch][index * 2 + 1]; /* Decode 14 samples. */ for (n = 0; n < 14; n++) { - int sampledat = get_sbits (&gb, 4); + int32_t sampledat; + if(n&1) sampledat= *src++ <<28; + else sampledat= (*src&0xF0)<<24; *samples = ((prev[ch][0]*factor1 - + prev[ch][1]*factor2) >> 11) + (sampledat << exp); + + prev[ch][1]*factor2) >> 11) + (sampledat>>exp); prev[ch][1] = prev[ch][0]; prev[ch][0] = *samples++; |