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Diffstat (limited to 'media/libopus/src/opus.c')
| -rw-r--r-- | media/libopus/src/opus.c | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/media/libopus/src/opus.c b/media/libopus/src/opus.c new file mode 100644 index 000000000..f76f125cf --- /dev/null +++ b/media/libopus/src/opus.c @@ -0,0 +1,356 @@ +/* Copyright (c) 2011 Xiph.Org Foundation, Skype Limited + Written by Jean-Marc Valin and Koen Vos */ +/* + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + - Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + - Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER + OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "opus.h" +#include "opus_private.h" + +#ifndef DISABLE_FLOAT_API +OPUS_EXPORT void opus_pcm_soft_clip(float *_x, int N, int C, float *declip_mem) +{ + int c; + int i; + float *x; + + if (C<1 || N<1 || !_x || !declip_mem) return; + + /* First thing: saturate everything to +/- 2 which is the highest level our + non-linearity can handle. At the point where the signal reaches +/-2, + the derivative will be zero anyway, so this doesn't introduce any + discontinuity in the derivative. */ + for (i=0;i<N*C;i++) + _x[i] = MAX16(-2.f, MIN16(2.f, _x[i])); + for (c=0;c<C;c++) + { + float a; + float x0; + int curr; + + x = _x+c; + a = declip_mem[c]; + /* Continue applying the non-linearity from the previous frame to avoid + any discontinuity. */ + for (i=0;i<N;i++) + { + if (x[i*C]*a>=0) + break; + x[i*C] = x[i*C]+a*x[i*C]*x[i*C]; + } + + curr=0; + x0 = x[0]; + while(1) + { + int start, end; + float maxval; + int special=0; + int peak_pos; + for (i=curr;i<N;i++) + { + if (x[i*C]>1 || x[i*C]<-1) + break; + } + if (i==N) + { + a=0; + break; + } + peak_pos = i; + start=end=i; + maxval=ABS16(x[i*C]); + /* Look for first zero crossing before clipping */ + while (start>0 && x[i*C]*x[(start-1)*C]>=0) + start--; + /* Look for first zero crossing after clipping */ + while (end<N && x[i*C]*x[end*C]>=0) + { + /* Look for other peaks until the next zero-crossing. */ + if (ABS16(x[end*C])>maxval) + { + maxval = ABS16(x[end*C]); + peak_pos = end; + } + end++; + } + /* Detect the special case where we clip before the first zero crossing */ + special = (start==0 && x[i*C]*x[0]>=0); + + /* Compute a such that maxval + a*maxval^2 = 1 */ + a=(maxval-1)/(maxval*maxval); + /* Slightly boost "a" by 2^-22. This is just enough to ensure -ffast-math + does not cause output values larger than +/-1, but small enough not + to matter even for 24-bit output. */ + a += a*2.4e-7; + if (x[i*C]>0) + a = -a; + /* Apply soft clipping */ + for (i=start;i<end;i++) + x[i*C] = x[i*C]+a*x[i*C]*x[i*C]; + + if (special && peak_pos>=2) + { + /* Add a linear ramp from the first sample to the signal peak. + This avoids a discontinuity at the beginning of the frame. */ + float delta; + float offset = x0-x[0]; + delta = offset / peak_pos; + for (i=curr;i<peak_pos;i++) + { + offset -= delta; + x[i*C] += offset; + x[i*C] = MAX16(-1.f, MIN16(1.f, x[i*C])); + } + } + curr = end; + if (curr==N) + break; + } + declip_mem[c] = a; + } +} +#endif + +int encode_size(int size, unsigned char *data) +{ + if (size < 252) + { + data[0] = size; + return 1; + } else { + data[0] = 252+(size&0x3); + data[1] = (size-(int)data[0])>>2; + return 2; + } +} + +static int parse_size(const unsigned char *data, opus_int32 len, opus_int16 *size) +{ + if (len<1) + { + *size = -1; + return -1; + } else if (data[0]<252) + { + *size = data[0]; + return 1; + } else if (len<2) + { + *size = -1; + return -1; + } else { + *size = 4*data[1] + data[0]; + return 2; + } +} + +int opus_packet_get_samples_per_frame(const unsigned char *data, + opus_int32 Fs) +{ + int audiosize; + if (data[0]&0x80) + { + audiosize = ((data[0]>>3)&0x3); + audiosize = (Fs<<audiosize)/400; + } else if ((data[0]&0x60) == 0x60) + { + audiosize = (data[0]&0x08) ? Fs/50 : Fs/100; + } else { + audiosize = ((data[0]>>3)&0x3); + if (audiosize == 3) + audiosize = Fs*60/1000; + else + audiosize = (Fs<<audiosize)/100; + } + return audiosize; +} + +int opus_packet_parse_impl(const unsigned char *data, opus_int32 len, + int self_delimited, unsigned char *out_toc, + const unsigned char *frames[48], opus_int16 size[48], + int *payload_offset, opus_int32 *packet_offset) +{ + int i, bytes; + int count; + int cbr; + unsigned char ch, toc; + int framesize; + opus_int32 last_size; + opus_int32 pad = 0; + const unsigned char *data0 = data; + + if (size==NULL || len<0) + return OPUS_BAD_ARG; + if (len==0) + return OPUS_INVALID_PACKET; + + framesize = opus_packet_get_samples_per_frame(data, 48000); + + cbr = 0; + toc = *data++; + len--; + last_size = len; + switch (toc&0x3) + { + /* One frame */ + case 0: + count=1; + break; + /* Two CBR frames */ + case 1: + count=2; + cbr = 1; + if (!self_delimited) + { + if (len&0x1) + return OPUS_INVALID_PACKET; + last_size = len/2; + /* If last_size doesn't fit in size[0], we'll catch it later */ + size[0] = (opus_int16)last_size; + } + break; + /* Two VBR frames */ + case 2: + count = 2; + bytes = parse_size(data, len, size); + len -= bytes; + if (size[0]<0 || size[0] > len) + return OPUS_INVALID_PACKET; + data += bytes; + last_size = len-size[0]; + break; + /* Multiple CBR/VBR frames (from 0 to 120 ms) */ + default: /*case 3:*/ + if (len<1) + return OPUS_INVALID_PACKET; + /* Number of frames encoded in bits 0 to 5 */ + ch = *data++; + count = ch&0x3F; + if (count <= 0 || framesize*count > 5760) + return OPUS_INVALID_PACKET; + len--; + /* Padding flag is bit 6 */ + if (ch&0x40) + { + int p; + do { + int tmp; + if (len<=0) + return OPUS_INVALID_PACKET; + p = *data++; + len--; + tmp = p==255 ? 254: p; + len -= tmp; + pad += tmp; + } while (p==255); + } + if (len<0) + return OPUS_INVALID_PACKET; + /* VBR flag is bit 7 */ + cbr = !(ch&0x80); + if (!cbr) + { + /* VBR case */ + last_size = len; + for (i=0;i<count-1;i++) + { + bytes = parse_size(data, len, size+i); + len -= bytes; + if (size[i]<0 || size[i] > len) + return OPUS_INVALID_PACKET; + data += bytes; + last_size -= bytes+size[i]; + } + if (last_size<0) + return OPUS_INVALID_PACKET; + } else if (!self_delimited) + { + /* CBR case */ + last_size = len/count; + if (last_size*count!=len) + return OPUS_INVALID_PACKET; + for (i=0;i<count-1;i++) + size[i] = (opus_int16)last_size; + } + break; + } + /* Self-delimited framing has an extra size for the last frame. */ + if (self_delimited) + { + bytes = parse_size(data, len, size+count-1); + len -= bytes; + if (size[count-1]<0 || size[count-1] > len) + return OPUS_INVALID_PACKET; + data += bytes; + /* For CBR packets, apply the size to all the frames. */ + if (cbr) + { + if (size[count-1]*count > len) + return OPUS_INVALID_PACKET; + for (i=0;i<count-1;i++) + size[i] = size[count-1]; + } else if (bytes+size[count-1] > last_size) + return OPUS_INVALID_PACKET; + } else + { + /* Because it's not encoded explicitly, it's possible the size of the + last packet (or all the packets, for the CBR case) is larger than + 1275. Reject them here.*/ + if (last_size > 1275) + return OPUS_INVALID_PACKET; + size[count-1] = (opus_int16)last_size; + } + + if (payload_offset) + *payload_offset = (int)(data-data0); + + for (i=0;i<count;i++) + { + if (frames) + frames[i] = data; + data += size[i]; + } + + if (packet_offset) + *packet_offset = pad+(opus_int32)(data-data0); + + if (out_toc) + *out_toc = toc; + + return count; +} + +int opus_packet_parse(const unsigned char *data, opus_int32 len, + unsigned char *out_toc, const unsigned char *frames[48], + opus_int16 size[48], int *payload_offset) +{ + return opus_packet_parse_impl(data, len, 0, out_toc, + frames, size, payload_offset, NULL); +} + |