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/*
* FILE: codec_l8.c
* AUTHORS: Orion Hodson
*
* Copyright (c) 1998-2001 University College London
* All rights reserved.
*/
#ifndef HIDE_SOURCE_STRINGS
static const char cvsid[] =
"$Id: codec_l8.c,v 1.1 2001/01/11 21:41:16 ucacoxh Exp $";
#endif /* HIDE_SOURCE_STRINGS */
#include "config_unix.h"
#include "config_win32.h"
#include "memory.h"
#include "util.h"
#include "debug.h"
#include "audio_types.h"
#include "codec_types.h"
#include "codec_l8.h"
/* Note payload numbers are dynamic and selected so:
* (a) we always have one codec that can be used at each sample rate and freq
* (b) to backwards match earlier releases.
*/
static codec_format_t cs[] = {
{"Linear-8", "L8-8K-Mono",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 160, {DEV_S16, 8000, 16, 1, 160 * BYTES_PER_SAMPLE}}, /* 20 ms */
{"Linear-8", "L8-8K-Stereo",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 320, {DEV_S16, 8000, 16, 2, 2 * 160 * BYTES_PER_SAMPLE}}, /* 20 ms */
{"Linear-8", "L8-16K-Mono",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 160, {DEV_S16, 16000, 16, 1, 160 * BYTES_PER_SAMPLE}}, /* 10 ms */
{"Linear-8", "L8-16K-Stereo",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 320, {DEV_S16, 16000, 16, 2, 2 * 160 * BYTES_PER_SAMPLE}}, /* 10 ms */
{"Linear-8", "L8-32K-Mono",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 160, {DEV_S16, 32000, 16, 1, 160 * BYTES_PER_SAMPLE}}, /* 5 ms */
{"Linear-8", "L8-32K-Stereo",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 320, {DEV_S16, 32000, 16, 2, 2 * 160 * BYTES_PER_SAMPLE}}, /* 5 ms */
{"Linear-8", "L8-44K-Mono",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 160, {DEV_S16, 44100, 16, 1, 160 * BYTES_PER_SAMPLE}}, /* 3.6 ms */
{"Linear-8", "L8-44K-Stereo",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 320, {DEV_S16, 44100, 16, 2, 2 * 160 * BYTES_PER_SAMPLE}}, /* 3.6 ms */
{"Linear-8", "L8-48K-Mono",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 160, {DEV_S16, 48000, 16, 1, 160 * BYTES_PER_SAMPLE}}, /* 3.3 ms */
{"Linear-8", "L8-48K-Stereo",
"Linear 8 uncompressed audio.",
CODEC_PAYLOAD_DYNAMIC, 0, 320, {DEV_S16, 48000, 16, 2, 2 * 160 * BYTES_PER_SAMPLE}} /* 3.3 ms */
};
#define L8_NUM_FORMATS sizeof(cs)/sizeof(codec_format_t)
uint16_t
l8_get_formats_count()
{
return (uint16_t)L8_NUM_FORMATS;
}
const codec_format_t *
l8_get_format(uint16_t idx)
{
assert(idx < L8_NUM_FORMATS);
return &cs[idx];
}
/*
* "From draft-ietf-avt-profile-09.txt
*
* 4.5.12 L8
*
* L8 denotes linear audio data samples, using 8-bits of precision with
* an offset of 128, that is, the most negative signal is encoded as
* zero."
*/
int
l8_encode(uint16_t idx, u_char *state, sample *src, coded_unit *out)
{
uint8_t *dst;
uint32_t i, samples;
assert(idx < L8_NUM_FORMATS);
UNUSED(state);
out->state = NULL;
out->state_len = 0;
out->data_len = cs[idx].mean_coded_frame_size;
out->data = (u_char*)block_alloc(out->data_len);
samples = out->data_len;
dst = (uint8_t*)out->data;
for (i = 0; i < samples; i++) {
dst[i] = (uint8_t)((src[i] >> 8) + 128);
}
return samples;
}
int
l8_decode(uint16_t idx, u_char *state, coded_unit *in, sample *dst)
{
int samples, i;
uint8_t *src;
assert(idx < L8_NUM_FORMATS);
UNUSED(state);
samples = in->data_len;
src = (uint8_t*)in->data;
for (i = 0; i < samples; i++) {
dst[i] = (((sample)src[i]) - 128) << 8;
}
return samples;
}
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