Created by the British Broadcasting Corporation.
C interface to Dirac Encoder. More...
#include <libdirac_common/dirac_inttypes.h>#include <libdirac_common/dirac_types.h>Go to the source code of this file.
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);
| typedef VideoFormat dirac_encoder_presets_t |
Enumerated type that defines encoder presets that set the encoder and sequence paramters. More presets may be added in future
| typedef MVPrecisionType dirac_mvprecision_t |
Enumerated type that defines motion vector precisions supported by the encoder.
| typedef PrefilterType dirac_prefilter_t |
Enumerated type that defines prefiltering types supported by the encoder.
| DllExport void dirac_encoder_close | ( | dirac_encoder_t * | encoder | ) |
Free resources held by encoder
| encoder | Encoder Handle |
| DllExport void dirac_encoder_context_init | ( | dirac_encoder_context_t * | enc_ctx, |
| dirac_encoder_presets_t | preset | ||
| ) |
Function that creates an encoder context based on a preset value. The values can then be overridden by the user by setting each field separately
| enc_ctx | pointer to Encoder context tp be initialised. |
| preset | Preset to be used to initialise the encoder context
For a full list of video formats presets supported and the default values
of the source and encoder parameters. refer to Annex C of the Dirac
ByteStream Specification.
|
| DllExport void dirac_encoder_end_sequence | ( | dirac_encoder_t * | encoder | ) |
Request the encoder to end the sequence.
| encoder | Encoder Handle |
| DllExport dirac_encoder_t* dirac_encoder_init | ( | const dirac_encoder_context_t * | enc_ctx, |
| int | verbose | ||
| ) |
Initialise encoder. Makes a copy of the enc_ctx passed to it.
| enc_ctx | Parameters to initialise encoder context |
| verbose | boolean flag to set verbose output |
| DllExport int dirac_encoder_load | ( | dirac_encoder_t * | encoder, |
| unsigned char * | uncdata, | ||
| int | uncdata_size | ||
| ) |
Load uncompressed data into the encoder. Expects one full frame of data
| encoder | Encoder Handle |
| uncdata | Uncompressed data buffer |
| uncdata_size | boolean flag to set verbose output |
| DllExport dirac_encoder_state_t dirac_encoder_output | ( | dirac_encoder_t * | encoder | ) |
Retrieve an encoded frame from the encoder. Returns the state of the encoder. The encoder buffer enc_buf in the encodermust be set up with the buffer and buffer_size that will hold the encoded frame
| encoder | Encoder Handle |
© 2004 British Broadcasting Corporation.
Dirac code licensed under the Mozilla Public License (MPL) Version 1.1.
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