Hello all,
I've been writing a basic encoder using libFLAC++. It seems to work fine, as in the
resultant file is playable in any FLAC compatible player, however the compression
ratio is very small - the main example being a 60MB file compressing to 54MB, i guess
there's an option i've missed, but i cannot track it down. I was hoping someone could
point it out for me:
FLAC::Encoder::File flac;
void setup()
{
FLAC__FileEncoderState state;
flac.set_filename(output_filename.c_str());
flac.set_channels (2);
flac.set_bits_per_sample (16);
flac.set_sample_rate (44100);
flac.set_do_exhaustive_model_search(false);
flac.set_do_escape_coding(false);
flac.set_do_mid_side_stereo(true);
flac.set_loose_mid_side_stereo(false);
flac.set_qlp_coeff_precision(0);
flac.set_min_residual_partition_order(3);
flac.set_max_residual_partition_order(3);
flac.set_rice_parameter_search_dist(0);
flac.set_max_lpc_order(8);
state = flac.init();
}
int write(long num_bytes, unsigned char *buffer)
{
int32_t sample[1176]; // sample
numbers are set to one frame of a CD
samples = 588; // which
contains 588 samples per channel per frame
int j=0;
for (int i=0; i<2352; i+=4) { // Converting
unsigned char to signed long
sample[j++] = buffer[i] + (buffer[i+1] << 8);
sample[j++] = buffer[i+2] + (buffer[i+3] << 8);
}
flac.process_interleaved((const FLAC__int32*)&sample[0], samples);
}
void finish()
{
flac.finish();
}
These are actually class members, but i've pulled them out to try and make it easier
to spot any mistakes. I've tried to set it up to have an equivalent to quality level 5
on the command line flac utility. I'm pulling the bytes off a CD hence the reason they
are in char format when they enter the write loop. The write loop is called for every
frame (i've tried changing this - writing to the the process function with a larger
buffer, but it doesn't seem to make any difference).
Any ideas anyone?
Thanks
Andrew
_______________________________________________
Flac-dev mailing list
[EMAIL PROTECTED]
http://lists.xiph.org/mailman/listinfo/flac-dev
