A set of 'C' functions that define the public interface to the Dirac encoder. Refer to the the reference encoder source code, encoder/encmain.cpp for an example of how to use the "C" interface. The pseudocode below gives a brief description of the "C" interface usage.
#include <libdirac_decoder/dirac_encoder.h>
#define ENCBUF_SIZE 1024*1024;
unsigned char *buffer, enc_buf[ENC_BUFSIZE];
int buffer_size;
dirac_encoder_t *encoder;
dirac_encoder_context_t enc_ctx;
// Initialse the encoder context with the presets for SD576 - Standard
// Definition Digital
dirac_encoder_context_init (&enc_ctx, VIDEO_FORMAT_SD576I50);
// Override parameters if required
// interlace : 1 - interlaced; 0 - progressive
enc_ctx.seq_params.interlace = 0;
enc_ctx.seq_params.topfieldfirst = 0;
enc_ctx.enc_params.qf = 7.5;
// disable instrumentation flag
enc_ctx.instr_flag = 0;
// return locally decoded output
enc_ctx.decode_flag = 1;
// Initialise the encoder with the encoder context.
// Setting verbose output to false
encoder= dirac_encoder_init(&enc_ctx, false);
// Set the buffer size. For SD576 4:2:0 chroma
buffer_size = (720*576*3)/2;
buffer = (unsigned char *)malloc (buffer_size);
// Output buffer
dirac_encoder_state_t state;
int go = 1;
do
{
read uncompressed frame data into buffer
if (end of file)
{
// push end of sequence
dirac_encoder_end_sequence(encoder);
}
// load one frame of data into encoder
if (dirac_encoder_load(encoder, buffer, buffer_size) == 0)
{
// Retrieve encoded frames from encoder
do
{
encoder->enc_buf.buffer = enc_buf;
encoder->enc_buf.size = ENCBUF_SIZE;
state = dirac_encoder_output (encoder);
switch (state)
{
case ENC_STATE_AVAIL:
// Encoded frame available in encoder->enc_buf
// Encoded frame params available in enccoder->enc_fparams
// Encoded frame stats available in enccoder->enc_fstats
break;
case ENC_STATE_BUFFER:
break;
case ENC_STATE_EOS:
// Reached end of sequence
// End of sequence information is available in encoder->enc_buf
// Sequence statistics available in encoder->enc_seqstats;
go = 0; // exit from the encoding loop
break;
case ENC_STATE_INVALID:
default:
// Unrecoverable error encountered. Exit;
exit (exit code);
}
if (encoder->decoded_frame_avail)
{
//locally decoded frame is available in
//encoder->dec_buf
//locally decoded frame parameters available
//in encoder->dec_fparams
}
if (encoder->instr_data_avail)
{
//Instrumentation data (motion vectors etc.)
//available in encoder->instr
}
} while (state == ENC_STATE_AVAIL)
}
} while (go == 1);
// Free the encoder resources
dirac_encoder_close(encoder)
// Free the uncompressed data buffer
free (buffer);