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/* Iridium AMBE vocoder - Decoder tool */
/* (C) 2015 by Sylvain Munaut <tnt@246tNt.com>
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <string.h>
#include "ambe.h"
static const uint8_t wav_hdr[] = {
/* WAV header */
'R', 'I', 'F', 'F', /* ChunkID */
0x00, 0x00, 0x00, 0x00, /* ChunkSize */
'W', 'A', 'V', 'E', /* Format */
/* Sub chunk: format */
'f', 'm', 't', ' ', /* Subchunk1ID */
0x10, 0x00, 0x00, 0x00, /* Subchunk1Size */
0x01, 0x00, /* AudioFormat: PCM */
0x01, 0x00, /* NumChannels: Mono */
0x40, 0x1f, 0x00, 0x00, /* SampleRate: 8000 Hz */
0x80, 0x3e, 0x00, 0x00, /* ByteRate: 16k/s */
0x02, 0x00, /* BlockAlign: 2 bytes */
0x10, 0x00, /* BitsPerSample: 16 */
/* Sub chunk: data */
'd', 'a', 't', 'a', /* Subchunk2ID */
0x00, 0x00, 0x00, 0x00, /* Subchunk2Size */
};
static uint32_t
le32(uint32_t v)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
return v;
#else
return ((v & 0x000000ff) << 24) |
((v & 0x0000ff00) << 8) |
((v & 0x00ff0000) >> 8) |
((v & 0xff000000) >> 24);
#endif
}
static uint16_t
le16(uint16_t v)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
return v;
#else
return ((v & 0x00ff) << 8) |
((v & 0xff00) >> 8);
#endif
}
int main(int argc, char *argv[])
{
struct ir77_ambe_decoder *dec = NULL;
FILE *fin, *fout;
int is_wave = 0, l, rv;
int frames_ok = 0, frames_total = 0;
float error_ratio = 1.0f;
/* Arguments */
if (argc > 3) {
fprintf(stderr, "Usage: %s [in_file [out_file]]\n", argv[0]);
return -1;
}
if ((argc < 2) || !strcmp(argv[1], "-"))
fin = stdin;
else {
fin = fopen(argv[1], "rb");
if (!fin) {
fprintf(stderr, "[!] Unable to open input file\n");
return -1;
}
}
if ((argc < 3) || !strcmp(argv[2], "-"))
fout = stdout;
else {
fout = fopen(argv[2], "wb");
if (!fout) {
fprintf(stderr, "[!] Unable to open output file\n");
return -1;
}
l = strlen(argv[2]);
if ((l > 4) && (!strcmp(".wav", &argv[2][l-4])))
is_wave = 1;
}
/* Write inital wave header */
if (is_wave) {
rv = fwrite(wav_hdr, sizeof(wav_hdr), 1, fout);
if (rv != 1) {
fprintf(stderr, "[!] Failed to write WAV header\n");
goto exit;
}
}
/* Init decoder */
dec = ir77_ambe_decode_alloc();
if (!dec)
goto exit;
/* Process all frames */
l = 0;
while (!feof(fin))
{
uint8_t superframe[39];
int16_t audio[2*360];
int rv, i;
/* Read input frame */
rv = fread(superframe, 1, 39, fin);
if (rv != 39)
break;
/* Skip dummy frames */
if ((superframe[0] == 0xff) && (superframe[38] == 0xff))
continue;
/* Decompress */
rv = ir77_ambe_decode_superframe(dec, audio, 2*360, superframe);
if (rv < 0) {
fprintf(stderr, "[!] codec error\n");
break;
}
frames_ok += rv;
frames_total += 2;
/* Write audio output */
for (i=0; i<2*360; i++)
audio[i] = le16(audio[i]);
rv = fwrite(audio, 2, 2*360, fout);
if (rv != 2*360) {
fprintf(stderr, "[!] short write\n");
break;
}
/* Keep track of number of samples */
l += 2*360;
}
/* Report the frame error ratio */
error_ratio = 1.0f - (1.0f * frames_ok) / frames_total;
fprintf(stderr, "Error ratio: %.2f\n", error_ratio);
/* Release decoder */
ir77_ambe_decode_release(dec);
/* Fix wave header */
if (is_wave)
{
uint32_t v;
/* Fixup Subchunk2Size */
v = le32(l * 2);
rv = fseek(fout, 40, SEEK_SET);
if (rv < 0)
goto exit;
rv = fwrite(&v, 4, 1, fout);
if (rv < 0)
goto exit;
/* Fixup ChunkSize */
v = le32(l * 2 + 36);
rv = fseek(fout, 4, SEEK_SET);
if (rv < 0)
goto exit;
rv = fwrite(&v, 4, 1, fout);
if (rv < 0)
goto exit;
}
exit:
/* Close in/out */
fclose(fout);
fclose(fin);
/* All done ! */
return error_ratio < 0.5f ? 0 : 1;
}
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