dirac_encoder.h File Reference

C interface to Dirac Encoder. More...

#include <libdirac_common/dirac_types.h>

Go to the source code of this file.

Classes
struct	dirac_encparams_t
struct	dirac_encoder_context_t
struct	dirac_enc_data_t
struct	dirac_enc_framestats_t
struct	dirac_enc_seqstats_t
struct	dirac_mv_t
struct	dirac_mv_cost_t
struct	dirac_instr_t
struct	dirac_encoder_t
Enumerations
enum	dirac_encoder_state_t
enum	dirac_encoder_presets_t
Functions
DllExport void	dirac_encoder_context_init (dirac_encoder_context_t *enc_ctx, dirac_encoder_presets_t preset)
DllExport dirac_encoder_t *	dirac_encoder_init (const dirac_encoder_context_t *enc_ctx, int verbose)
DllExport int	dirac_encoder_load (dirac_encoder_t *encoder, unsigned char *uncdata, int uncdata_size)
DllExport dirac_encoder_state_t	dirac_encoder_output (dirac_encoder_t *encoder)
DllExport int	dirac_encoder_end_sequence (dirac_encoder_t *encoder)
DllExport void	dirac_encoder_close (dirac_encoder_t *encoder)

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Detailed Description

C interface to Dirac Encoder.

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, SD576);

 // 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;

 while (read uncompressed frame data into buffer)
 {
    // 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_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)
    }
 }
 // Retrieve end of sequence info
 encoder->enc_buf.buffer = video_buf;
 encoder->enc_buf.size = VIDEO_BUFFER_SIZE;
 dirac_encoder_end_sequence( encoder );
 // End of sequence info is availale in encoder->enc_buf
 // Sequence statistics available in encoder->enc_seqstats;

 // Free the encoder resources
 dirac_encoder_close(encoder)
 // Free the uncompressed data buffer
 free (buffer);

 

Definition in file dirac_encoder.h.

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Enumeration Type Documentation

enum dirac_encoder_presets_t

Enumerated type that defines encoder presets that set the encoder and sequence paramters. More presets may be added in future Definition at line 155 of file dirac_encoder.h.

enum dirac_encoder_state_t

Enumerated type that defines encoder state Definition at line 146 of file dirac_encoder.h.

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Function Documentation

DllExport void dirac_encoder_close (  dirac_encoder_t *  encoder  )

Free resources held by encoder Parameters: encoder  Encoder Handle Definition at line 925 of file dirac_encoder.cpp.

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 Parameters: enc_ctx  pointer to Encoder context tp be initialised. preset  Preset to be used to initialise the encoder context The sequence parameters and encoder parameters are initialised as follows Sequence Parameters: Preset Field Value CIF width 352 height 288 chroma Planar YUV 4:2:0 chroma_width calculated from width and chroma chroma_height calculated from height and chroma frame_rate 13/1 interlace 0 (progressive) topfieldfirst 0 SD576 width 720 height 576 chroma Planar YUV 4:2:0 chroma_width calculated from width and chroma chroma_height calculated from height and chroma frame_rate 25/1 interlace 1 (interlaced) topfieldfirst 1 HD720 width 1280 height 720 chroma Planar YUV 4:2:0 chroma_width calculated from width and chroma chroma_height calculated from height and chroma frame_rate 50/1 interlace 0 (progressive) topfieldfirst 0 HD1080 width 1920 height 1080 chroma Planar YUV 4:2:0 chroma_width calculated from width and chroma chroma_height calculated from height and chroma frame_rate 25/1 interlace 1 (interlaced) topfieldfirst 1 Encoder params: Preset Field Value CIF qf 7 L1_sep 3 num_L1 11 cpd 20.0 xblen 12 yblen 12 xbsep 8 ybsep 8 SD576 qf 7 L1_sep 3 num_L1 3 cpd 32.0 xblen 12 yblen 12 xbsep 8 ybsep 8 HD720 qf 7 L1_sep 3 num_L1 7 cpd 20.0 xblen 16 yblen 16 xbsep 10 ybsep 12 HD1080 qf 7 L1_sep 3 num_L1 3 cpd 32.0 xblen 20 yblen 20 xbsep 16 ybsep 16 Definition at line 804 of file dirac_encoder.cpp.

DllExport int dirac_encoder_end_sequence (  dirac_encoder_t *  encoder  )

Retrieve end of sequence information from the encoder. The encoder buffer, enc_buf, in the encodermust be set up with the buffer and buffer_size that will hold the end of sequence information. Parameters: encoder  Encoder Handle Returns: return status. >=0 - successful; -1 failed Definition at line 895 of file dirac_encoder.cpp. References DiracEncoder::GetDecodedData(), and DiracEncoder::GetSequenceEnd().

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. Parameters: enc_ctx  Parameters to initialise encoder context verbose  boolean flag to set verbose output Returns: encoder Handle to encoder if successful or NULL on failure Definition at line 812 of file dirac_encoder.cpp. References dirac_encoder_t::decoded_frame_avail, dirac_encoder_t::encoded_frame_avail, and dirac_encoder_t::instr_data_avail.

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 Parameters: encoder  Encoder Handle uncdata  Uncompressed data buffer uncdata_size  boolean flag to set verbose output Returns: return status. >0 - successful; -1 failed Failure may be due to input data size not matching the required frame size. Definition at line 833 of file dirac_encoder.cpp. References dirac_encoder_t::compressor, DiracEncoder::GetEncParams(), DiracEncoder::LoadNextFrame(), and dirac::CodecParams::Verbose().

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 Parameters: encoder  Encoder Handle Returns: ENC_STATE_INVALID - unrecoverable error ENC_STATE_BUFFER - load data into encoder ENC_STATE_AVAIL - Encoded frame available Definition at line 856 of file dirac_encoder.cpp. References DiracEncoder::CompressNextFrame(), DiracEncoder::GetDecodedData(), and DiracEncoder::GetEncodedData().

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