diff options
Diffstat (limited to 'src/libmpg123/layer1.c')
| -rwxr-xr-x | src/libmpg123/layer1.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/src/libmpg123/layer1.c b/src/libmpg123/layer1.c new file mode 100755 index 0000000..057f08b --- /dev/null +++ b/src/libmpg123/layer1.c @@ -0,0 +1,187 @@ + +/* + * Mpeg Layer-1 audio decoder + * -------------------------- + * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README' + * near unoptimzed ... + * + * may have a few bugs after last optimization ... + * + */ + +#include "mpg123.h" +#include "getbits.h" + +/* Used by the getbits macros */ +static unsigned long rval; + +void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT], struct frame *fr) +{ + unsigned int *ba = balloc; + unsigned int *sca = (unsigned int *) scale_index; + + if (fr->stereo) + { + int i; + int jsbound = fr->jsbound; + + for (i = 0; i < jsbound; i++) + { + *ba++ = mpg123_getbits(4); + *ba++ = mpg123_getbits(4); + } + for (i = jsbound; i < SBLIMIT; i++) + *ba++ = mpg123_getbits(4); + + ba = balloc; + + for (i = 0; i < jsbound; i++) + { + if ((*ba++)) + *sca++ = mpg123_getbits(6); + if ((*ba++)) + *sca++ = mpg123_getbits(6); + } + for (i = jsbound; i < SBLIMIT; i++) + if ((*ba++)) + { + *sca++ = mpg123_getbits(6); + *sca++ = mpg123_getbits(6); + } + } + else + { + int i; + + for (i = 0; i < SBLIMIT; i++) + *ba++ = mpg123_getbits(4); + ba = balloc; + for (i = 0; i < SBLIMIT; i++) + if ((*ba++)) + *sca++ = mpg123_getbits(6); + } +} + +void I_step_two(real fraction[2][SBLIMIT], unsigned int balloc[2 * SBLIMIT], + unsigned int scale_index[2][SBLIMIT], struct frame *fr) +{ + int i, n; + int smpb[2 * SBLIMIT]; /* values: 0-65535 */ + int *sample; + register unsigned int *ba; + register unsigned int *sca = (unsigned int *) scale_index; + + if (fr->stereo) + { + int jsbound = fr->jsbound; + register real *f0 = fraction[0]; + register real *f1 = fraction[1]; + + ba = balloc; + for (sample = smpb, i = 0; i < jsbound; i++) + { + if ((n = *ba++)) + *sample++ = mpg123_getbits(n + 1); + if ((n = *ba++)) + *sample++ = mpg123_getbits(n + 1); + } + for (i = jsbound; i < SBLIMIT; i++) + if ((n = *ba++)) + *sample++ = mpg123_getbits(n + 1); + + ba = balloc; + for (sample = smpb, i = 0; i < jsbound; i++) + { + if ((n = *ba++)) + *f0++ = (real) (((-1) << n) + (*sample++) + 1) * mpg123_muls[n + 1][*sca++]; + else + *f0++ = 0.0; + if ((n = *ba++)) + *f1++ = (real) (((-1) << n) + (*sample++) + 1) * mpg123_muls[n + 1][*sca++]; + else + *f1++ = 0.0; + } + for (i = jsbound; i < SBLIMIT; i++) + { + if ((n = *ba++)) + { + real samp = (((-1) << n) + (*sample++) + 1); + + *f0++ = samp * mpg123_muls[n + 1][*sca++]; + *f1++ = samp * mpg123_muls[n + 1][*sca++]; + } + else + *f0++ = *f1++ = 0.0; + } + for (i = fr->down_sample_sblimit; i < 32; i++) + fraction[0][i] = fraction[1][i] = 0.0; + } + else + { + register real *f0 = fraction[0]; + + ba = balloc; + for (sample = smpb, i = 0; i < SBLIMIT; i++) + if ((n = *ba++)) + *sample++ = mpg123_getbits(n + 1); + ba = balloc; + for (sample = smpb, i = 0; i < SBLIMIT; i++) + { + if ((n = *ba++)) + *f0++ = (real) (((-1) << n) + (*sample++) + 1) * mpg123_muls[n + 1][*sca++]; + else + *f0++ = 0.0; + } + for (i = fr->down_sample_sblimit; i < 32; i++) + fraction[0][i] = 0.0; + } +} + +int mpg123_do_layer1(struct frame *fr) +{ + int i, stereo = fr->stereo; + unsigned int balloc[2 * SBLIMIT]; + unsigned int scale_index[2][SBLIMIT]; + real fraction[2][SBLIMIT]; + int single = fr->single; + + fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32; + + if (stereo == 1 || single == 3) + single = 0; + + I_step_one(balloc, scale_index, fr); + + for (i = 0; i < SCALE_BLOCK; i++) + { + I_step_two(fraction, balloc, scale_index, fr); + + if (single >= 0) + { + (fr->synth_mono) ((real *) fraction[single], mpg123_pcm_sample, &mpg123_pcm_point); + } + else + { + int p1 = mpg123_pcm_point; + + (fr->synth) ((real *) fraction[0], 0, mpg123_pcm_sample, &p1); + (fr->synth) ((real *) fraction[1], 1, mpg123_pcm_sample, &mpg123_pcm_point); + } + +/*** + if (mpg123_info->output_audio) + { + + mpg123_ip.add_vis_pcm(mpg123_ip.output->written_time(), mpg123_cfg.resolution == 16 ? FMT_S16_NE : FMT_U8, + mpg123_cfg.channels == 2 ? fr->stereo : 1, mpg123_pcm_point, mpg123_pcm_sample); + while (mpg123_ip.output->buffer_free() < mpg123_pcm_point && mpg123_info->going && mpg123_info->jump_to_time == -1) + xmms_usleep(10000); + if (mpg123_info->going && mpg123_info->jump_to_time == -1) + mpg123_ip.output->write_audio(mpg123_pcm_sample, mpg123_pcm_point); + } +***/ + mpg123_pcm_point = 0; + } + + return 1; +} |