static int a52_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
AC3DecodeState *s = avctx->priv_data;
uint8_t *buf_ptr;
int flags, i, len;
int sample_rate, bit_rate;
short *out_samples = data;
float level;
static const int ac3_channels[8] = {
2, 1, 2, 3, 3, 4, 4, 5
};
buf_ptr = buf;
while (buf_size > 0) {
len = s->inbuf_ptr - s->inbuf;
if (s->frame_size == 0) {
/* no header seen : find one. We need at least 7 bytes to parse it */
len = HEADER_SIZE - len;
if (len > buf_size)
len = buf_size;
memcpy(s->inbuf_ptr, buf_ptr, len);
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
if ((s->inbuf_ptr - s->inbuf) == HEADER_SIZE) {
len = s->a52_syncinfo(s->inbuf, &s->flags, &sample_rate, &bit_rate);
if (len == 0) {
/* no sync found : move by one byte (inefficient, but simple!) */
memcpy(s->inbuf, s->inbuf + 1, HEADER_SIZE - 1);
s->inbuf_ptr--;
} else {
s->frame_size = len;
/* update codec info */
avctx->sample_rate = sample_rate;
s->channels = ac3_channels[s->flags & 7];
if (s->flags & A52_LFE)
s->channels++;
if (avctx->channels == 0)
/* No specific number of channel requested */
avctx->channels = s->channels;
else if (s->channels < avctx->channels) {
av_log(avctx, AV_LOG_ERROR, "ac3dec: AC3 Source channels are less than specified: output to %d channels.. (frmsize: %d)\n", s->channels, len);
avctx->channels = s->channels;
}
avctx->bit_rate = bit_rate;
}
}
} else if (len < s->frame_size) {
len = s->frame_size - len;
if (len > buf_size)
len = buf_size;
memcpy(s->inbuf_ptr, buf_ptr, len);
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
} else {
flags = s->flags;
if (avctx->channels == 1)
flags = A52_MONO;
else if (avctx->channels == 2)
flags = A52_STEREO;
else
flags |= A52_ADJUST_LEVEL;
level = 1;
if (s->a52_frame(s->state, s->inbuf, &flags, &level, 384)) {
fail:
s->inbuf_ptr = s->inbuf;
s->frame_size = 0;
continue;
}
for (i = 0; i < 6; i++) {
if (s->a52_block(s->state))
goto fail;
float_to_int(s->samples, out_samples + i * 256 * avctx->channels, avctx->channels);
}
s->inbuf_ptr = s->inbuf;
s->frame_size = 0;
*data_size = 6 * avctx->channels * 256 * sizeof(int16_t);
break;
}
}
return buf_ptr - buf;
}
static int a52_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
AC3DecodeState *s = avctx->priv_data;
int flags, i, len;
int sample_rate, bit_rate;
short *out_samples = data;
float level;
static const int ac3_channels[8] = {
2, 1, 2, 3, 3, 4, 4, 5
};
*data_size= 0;
if (buf_size < HEADER_SIZE) {
av_log(avctx, AV_LOG_ERROR, "Error decoding frame, not enough bytes for header\n");
return -1;
}
len = s->a52_syncinfo(buf, &s->flags, &sample_rate, &bit_rate);
if (len == 0) {
av_log(avctx, AV_LOG_ERROR, "Error decoding frame, no sync byte at begin\n");
return -1;
}
if (buf_size < len) {
av_log(avctx, AV_LOG_ERROR, "Error decoding frame, not enough bytes\n");
return -1;
}
/* update codec info */
avctx->sample_rate = sample_rate;
s->channels = ac3_channels[s->flags & 7];
if (s->flags & A52_LFE)
s->channels++;
if (avctx->request_channels > 0 &&
avctx->request_channels <= 2 &&
avctx->request_channels < s->channels) {
avctx->channels = avctx->request_channels;
} else {
avctx->channels = s->channels;
}
avctx->bit_rate = bit_rate;
flags = s->flags;
if (avctx->channels == 1)
flags = A52_MONO;
else if (avctx->channels == 2)
flags = A52_STEREO;
else
flags |= A52_ADJUST_LEVEL;
level = 1;
if (s->a52_frame(s->state, buf, &flags, &level, 384)) {
fail:
av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n");
return -1;
}
for (i = 0; i < 6; i++) {
if (s->a52_block(s->state))
goto fail;
float_to_int(s->samples, out_samples + i * 256 * avctx->channels, avctx->channels);
}
*data_size = 6 * avctx->channels * 256 * sizeof(int16_t);
return len;
}