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* Bluetooth low-complexity, subband codec (SBC) decoder
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* Copyright (C) 2004-2008 Marcel Holtmann <marcel@holtmann.org>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program 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
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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#include <sys/ioctl.h>
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#include <sys/soundcard.h>
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static void decode(char *filename, char *output, int tofile)
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unsigned char buf[BUF_SIZE], *stream;
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int fd, ad, pos, streamlen, framelen, count, written, len;
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int format = AFMT_S16_BE, frequency, channels;
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if (stat(filename, &st) < 0) {
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fprintf(stderr, "Can't get size of file %s: %s\n",
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filename, strerror(errno));
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filesize = st.st_size;
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stream = malloc(st.st_size);
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fprintf(stderr, "Can't allocate memory for %s: %s\n",
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filename, strerror(errno));
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fd = open(filename, O_RDONLY);
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fprintf(stderr, "Can't open file %s: %s\n",
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filename, strerror(errno));
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if (read(fd, stream, st.st_size) != st.st_size) {
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fprintf(stderr, "Can't read content of %s: %s\n",
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filename, strerror(errno));
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streamlen = st.st_size;
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ad = open(output, O_WRONLY | O_CREAT | O_TRUNC, 0644);
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ad = open(output, O_WRONLY, 0);
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fprintf(stderr, "Can't open output %s: %s\n",
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output, strerror(errno));
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framelen = sbc_decode(&sbc, stream, streamlen, buf, sizeof(buf), &len);
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channels = sbc.mode == SBC_MODE_MONO ? 1 : 2;
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switch (sbc.frequency) {
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printf("%d Hz, %d channels\n", frequency, channels);
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if (ioctl(ad, SNDCTL_DSP_SETFMT, &format) < 0) {
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fprintf(stderr, "Can't set audio format on %s: %s\n",
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output, strerror(errno));
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if (ioctl(ad, SNDCTL_DSP_CHANNELS, &channels) < 0) {
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"Can't set number of channels on %s: %s\n",
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output, strerror(errno));
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if (ioctl(ad, SNDCTL_DSP_SPEED, &frequency) < 0) {
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fprintf(stderr, "Can't set audio rate on %s: %s\n",
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output, strerror(errno));
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while (framelen > 0) {
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/* we have completed an sbc_decode at this point sbc.len is the
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* length of the frame we just decoded count is the number of
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* decoded bytes yet to be written */
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if (count + len >= BUF_SIZE) {
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/* buffer is too full to stuff decoded audio in so it
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* must be written to the device */
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written = write(ad, buf, count);
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if (count + len >= BUF_SIZE) {
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"buffer size of %d is too small for decoded"
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" data (%d)\n", BUF_SIZE, len + count);
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/* increase the count */
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/* push the pointer in the file forward to the next bit to be
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* decoded tell the decoder to decode up to the remaining
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* length of the file (!) */
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framelen = sbc_decode(&sbc, stream + pos, streamlen - pos,
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buf + count, sizeof(buf) - count,
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written = write(ad, buf, count);
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static void usage(void)
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printf("SBC decoder utility ver %s\n", VERSION);
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printf("Copyright (c) 2004-2008 Marcel Holtmann\n\n");
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"\tsbcdec [options] file(s)\n"
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"\t-h, --help Display help\n"
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"\t-v, --verbose Verbose mode\n"
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"\t-d, --device <dsp> Sound device\n"
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"\t-f, --file <file> Decode to a file\n"
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static struct option main_options[] = {
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{ "help", 0, 0, 'h' },
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{ "device", 1, 0, 'd' },
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{ "verbose", 0, 0, 'v' },
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{ "file", 1, 0, 'f' },
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int main(int argc, char *argv[])
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int i, opt, verbose = 0, tofile = 0;
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while ((opt = getopt_long(argc, argv, "+hvd:f:", main_options, NULL)) != -1) {
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output = strdup(optarg);
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output = strdup(optarg);
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for (i = 0; i < argc; i++)
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decode(argv[i], output ? output : "/dev/dsp", tofile);