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The mediastreamer library aims at providing modular media processing and I/O
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for linphone, but also for any telephony application.
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Copyright (C) 2001 Simon MORLAT simon.morlat@linphone.org
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#include "msLPC10encoder.h"
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extern MSCodecInfo LPC10info;
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/* The return value of each of these calls is the same as that
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returned by fread/fwrite, which should be the number of samples
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successfully read/written, not the number of bytes. */
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read_16bit_samples(INT16 int16samples[], float speech[], int n)
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/* Convert 16 bit integer samples to floating point values in the
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for (i = 0; i < n; i++) {
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speech[i] = ((float) int16samples[i]) / 32768.0;
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write_16bit_samples(INT16 int16samples[], float speech[], int n)
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/* Convert floating point samples in range [-1,+1] to 16 bit
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for (i = 0; i < n; i++) {
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real_sample = 32768.0 * speech[i];
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if (real_sample < -32768.0) {
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int16samples[i] = -32768;
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} else if (real_sample > 32767.0) {
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int16samples[i] = 32767;
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int16samples[i] = real_sample;
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Write the bits in bits[0] through bits[len-1] to file f, in "packed"
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bits is expected to be an array of len integer values, where each
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integer is 0 to represent a 0 bit, and any other value represents a 1
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bit. This bit string is written to the file f in the form of several
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8 bit characters. If len is not a multiple of 8, then the last
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character is padded with 0 bits -- the padding is in the least
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significant bits of the last byte. The 8 bit characters are "filled"
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in order from most significant bit to least significant.
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write_bits(unsigned char *data, INT32 *bits, int len)
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int i; /* generic loop variable */
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unsigned char mask; /* The next bit position within the
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variable "data" to place the next
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/* Fill in the array bits.
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* The first compressed output bit will be the most significant
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* bit of the byte, so initialize mask to 0x80. The next byte of
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* compressed data is initially 0, and the desired bits will be
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for (i = 0; i < len; i++) {
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/* Turn on the next bit of output data, if necessary. */
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* If the byte data is full, determined by mask becoming 0,
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* then write the byte to the output file, and reinitialize
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* data and mask for the next output byte. Also add the byte
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* if (i == len-1), because if len is not a multiple of 8,
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* then mask won't yet be 0. */
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if ((mask == 0) || (i == len-1)) {
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Read bits from file f into bits[0] through bits[len-1], in "packed"
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Read ceiling(len/8) characters from file f, if that many are available
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to read, otherwise read to the end of the file. The first character's
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8 bits, in order from MSB to LSB, are used to fill bits[0] through
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bits[7]. The second character's bits are used to fill bits[8] through
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bits[15], and so on. If ceiling(len/8) characters are available to
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read, and len is not a multiple of 8, then some of the least
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significant bits of the last character read are completely ignored.
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Every entry of bits[] that is modified is changed to either a 0 or a
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The number of bits successfully read is returned, and is always in the
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range 0 to len, inclusive. If it is less than len, it will always be
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read_bits(unsigned char *data, INT32 *bits, int len)
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int i,ind=0; /* generic loop variable */
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/* Unpack the array bits into coded_frame. */
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for (i = 0; i < len; i++) {
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c = (int)(data[ind]);
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if (c & (0x80 >> (i & 7))) {
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static MSLPC10EncoderClass *ms_LPC10encoder_class=NULL;
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MSFilter * ms_LPC10encoder_new(void)
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r=g_new(MSLPC10Encoder,1);
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ms_LPC10encoder_init(r);
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if (ms_LPC10encoder_class==NULL)
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ms_LPC10encoder_class=g_new(MSLPC10EncoderClass,1);
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ms_LPC10encoder_class_init(ms_LPC10encoder_class);
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MS_FILTER(r)->klass=MS_FILTER_CLASS(ms_LPC10encoder_class);
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return(MS_FILTER(r));
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/* FOR INTERNAL USE*/
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void ms_LPC10encoder_init(MSLPC10Encoder *r)
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ms_filter_init(MS_FILTER(r));
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MS_FILTER(r)->infifos=r->f_inputs;
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MS_FILTER(r)->outfifos=r->f_outputs;
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MS_FILTER(r)->r_mingran=LPC10_SAMPLES_PER_FRAME*2;
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memset(r->f_inputs,0,sizeof(MSFifo*)*MSLPC10ENCODER_MAX_INPUTS);
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memset(r->f_outputs,0,sizeof(MSFifo*)*MSLPC10ENCODER_MAX_INPUTS);
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r->lpc10_enc=create_lpc10_encoder_state();
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void ms_LPC10encoder_class_init(MSLPC10EncoderClass *klass)
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ms_filter_class_init(MS_FILTER_CLASS(klass));
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ms_filter_class_set_name(MS_FILTER_CLASS(klass),"LPC10Enc");
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MS_FILTER_CLASS(klass)->max_finputs=MSLPC10ENCODER_MAX_INPUTS;
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MS_FILTER_CLASS(klass)->max_foutputs=MSLPC10ENCODER_MAX_INPUTS;
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MS_FILTER_CLASS(klass)->r_maxgran=LPC10_SAMPLES_PER_FRAME*2;
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MS_FILTER_CLASS(klass)->w_maxgran=7;
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MS_FILTER_CLASS(klass)->destroy=(MSFilterDestroyFunc)ms_LPC10encoder_destroy;
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MS_FILTER_CLASS(klass)->process=(MSFilterProcessFunc)ms_LPC10encoder_process;
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MS_FILTER_CLASS(klass)->info=(MSFilterInfo*)&LPC10info;
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void ms_LPC10encoder_process(MSLPC10Encoder *r)
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float speech[LPC10_SAMPLES_PER_FRAME];
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INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];
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/* process output fifos, but there is only one for this class of filter*/
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err1=ms_fifo_get_read_ptr(fi,LPC10_SAMPLES_PER_FRAME*2,&s);
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err1=ms_fifo_get_write_ptr(fo,7,&d);
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read_16bit_samples((INT16*)s, speech, LPC10_SAMPLES_PER_FRAME);
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lpc10_encode(speech, bits, r->lpc10_enc);
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write_bits(d, bits, LPC10_BITS_IN_COMPRESSED_FRAME);
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void ms_LPC10encoder_uninit(MSLPC10Encoder *obj)
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free(obj->lpc10_enc);
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void ms_LPC10encoder_destroy( MSLPC10Encoder *obj)
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ms_LPC10encoder_uninit(obj);
added
removed
mediastreamer/msLPC10encoder.c
