/* This should be called with a unique decoder instance as the seeking
* it does triggers an FAAD bug which results in distorted audio due to
* retained state being corrupted. (One suspects NeAACDecPostSeekReset()
* should resolve the problem but experimentation suggests not and no
* documentation exists describing its use.) */
static int aac_count_time (struct aac_data *data)
{
NeAACDecFrameInfo frame_info;
int samples = 0, bytes = 0, frames = 0;
off_t file_size;
int16_t *sample_buf;
file_size = io_file_size (data->stream);
if (file_size == -1)
return -1;
if (io_seek(data->stream, file_size / 2, SEEK_SET) == -1)
return -1;
buffer_flush (data);
/* Guess track length by decoding the middle 50 frames which have
* more than 25% of samples having absolute values greater than 16. */
while (frames < 50) {
if (buffer_fill_frame (data) <= 0)
break;
sample_buf = NeAACDecDecode (data->decoder, &frame_info,
buffer_data (data), buffer_length (data));
if (frame_info.error == 0 && frame_info.samples > 0) {
unsigned int ix, zeroes = 0;
for (ix = 0; ix < frame_info.samples; ix += 1) {
if (RANGE(-16, sample_buf[ix], 16))
zeroes += 1;
}
if (zeroes * 4 < frame_info.samples) {
samples += frame_info.samples;
bytes += frame_info.bytesconsumed;
frames += 1;
}
}
if (frame_info.bytesconsumed == 0)
break;
buffer_consume (data, frame_info.bytesconsumed);
}
if (frames == 0)
return -1;
samples /= frames;
samples /= data->channels;
bytes /= frames;
return ((file_size / bytes) * samples) / data->sample_rate;
}
static int aac_count_time (struct aac_data *data)
{
NeAACDecFrameInfo frame_info;
int samples = 0, bytes = 0, frames = 0;
off_t file_size;
char *sample_buf;
long saved_pos;
file_size = io_file_size (data->stream);
if (file_size == -1)
return -1;
saved_pos = io_tell (data->stream);
/* guess track length by decoding the first 10 frames */
while (frames < 10) {
if (buffer_fill_frame(data) <= 0)
break;
sample_buf = NeAACDecDecode(data->decoder, &frame_info,
buffer_data(data), buffer_length(data));
if (frame_info.error == 0 && frame_info.samples > 0) {
samples += frame_info.samples;
bytes += frame_info.bytesconsumed;
frames++;
}
if (frame_info.bytesconsumed == 0)
break;
buffer_consume (data, frame_info.bytesconsumed);
}
if (io_seek(data->stream, saved_pos, SEEK_SET) == (off_t)-1) {
logit ("Can't seek after couting time");
return -1;
}
if (frames == 0)
return -1;
samples /= frames;
samples /= data->channels;
bytes /= frames;
return ((file_size / bytes) * samples) / data->sample_rate;
}
static void *aac_open_internal (struct io_stream *stream, const char *fname)
{
struct aac_data *data;
NeAACDecConfigurationPtr neaac_cfg;
unsigned char channels;
unsigned long sample_rate;
int n;
/* init private struct */
data = xcalloc (1, sizeof *data);
data->decoder = NeAACDecOpen();
/* set decoder config */
neaac_cfg = NeAACDecGetCurrentConfiguration(data->decoder);
neaac_cfg->outputFormat = FAAD_FMT_16BIT; /* force 16 bit audio */
neaac_cfg->downMatrix = 1; /* 5.1 -> stereo */
neaac_cfg->dontUpSampleImplicitSBR = 0; /* upsample, please! */
NeAACDecSetConfiguration(data->decoder, neaac_cfg);
if (stream)
data->stream = stream;
else {
data->stream = io_open (fname, 1);
if (!io_ok(data->stream)) {
decoder_error (&data->error, ERROR_FATAL, 0,
"Can't open AAC file: %s", io_strerror(data->stream));
return data;
}
}
/* find a frame */
if (buffer_fill_frame(data) <= 0) {
decoder_error (&data->error, ERROR_FATAL, 0,
"Not a valid (or unsupported) AAC file");
return data;
}
/* in case of a bug, make sure there is at least some data
* in the buffer for NeAACDecInit() to work with.
*/
if (buffer_fill_min(data, 256) <= 0) {
decoder_error (&data->error, ERROR_FATAL, 0,
"AAC file/stream too short");
return data;
}
/* init decoder, returns the length of the header (if any) */
channels = (unsigned char)data->channels;
sample_rate = data->sample_rate;
n = NeAACDecInit (data->decoder, buffer_data(data), buffer_length(data),
&sample_rate, &channels);
data->channels = channels;
data->sample_rate = (int)sample_rate;
if (n < 0) {
decoder_error (&data->error, ERROR_FATAL, 0,
"libfaad can't open this stream");
return data;
}
logit ("sample rate %dHz, channels %d", data->sample_rate, data->channels);
if (!data->sample_rate || !data->channels) {
decoder_error (&data->error, ERROR_FATAL, 0,
"Invalid AAC sound parameters");
return data;
}
/* skip the header */
logit ("skipping header (%d bytes)", n);
buffer_consume (data, n);
/*NeAACDecInitDRM(data->decoder, data->sample_rate, data->channels);*/
data->ok = 1;
return data;
}
