[melted] / src / modules / vorbis / producer_vorbis.c

/*
 * producer_vorbis.c -- vorbis producer
 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
 * Author: Charles Yates <charles.yates@pandora.be>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

// Local header files
#include "producer_vorbis.h"

// MLT Header files
#include <framework/mlt_frame.h>

// vorbis Header files
#include <vorbis/codec.h>
#include <vorbis/vorbisfile.h>

// System header files
#include <stdlib.h>
#include <string.h>

// Forward references.
static int producer_open( mlt_producer this, char *file );
static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index );

/** Constructor for libvorbis.
*/

mlt_producer producer_vorbis_init( char *file )
{
        mlt_producer this = NULL;

        // Check that we have a non-NULL argument
        if ( file != NULL )
        {
                // Construct the producer
                this = calloc( 1, sizeof( struct mlt_producer_s ) );

                // Initialise it
                if ( mlt_producer_init( this, NULL ) == 0 )
                {
                        // Get the properties
                        mlt_properties properties = mlt_producer_properties( this );

                        // Set the resource property (required for all producers)
                        mlt_properties_set( properties, "resource", file );

                        // Register our get_frame implementation
                        this->get_frame = producer_get_frame;

                        // Open the file
                        if ( producer_open( this, file ) != 0 )
                        {
                                // Clean up
                                mlt_producer_close( this );
                                this = NULL;
                        }
                }
        }

        return this;
}

/** Destuctor for ogg files.
*/

static void producer_file_close( void *file )
{
        if ( file != NULL )
        {
                // Close the ogg vorbis structure
                ov_clear( file );

                // Free the memory
                free( file );
        }
}

/** Open the file.
*/

static int producer_open( mlt_producer this, char *file )
{
        // FILE pointer for file
        FILE *input = fopen( file, "r" );

        // Error code to return
        int error = input == NULL;

        // Continue if file is open
        if ( error == 0 )
        {
                // OggVorbis file structure
                OggVorbis_File *ov = calloc( 1, sizeof( OggVorbis_File ) );

                // Attempt to open the stream
                error = ov == NULL || ov_open( input, ov, NULL, 0 ) != 0;

                // Assign to producer properties if successful
                if ( error == 0 )
                {
                        // Get the properties
                        mlt_properties properties = mlt_producer_properties( this );

                        // Assign the ov structure
                        mlt_properties_set_data( properties, "ogg_vorbis_file", ov, 0, producer_file_close, NULL );

                        if ( ov_seekable( ov ) )
                        {
                                // Get the length of the file
                        double length = ov_time_total( ov, -1 );

                                // We will treat everything with the producer fps
                                double fps = mlt_properties_get_double( properties, "fps" );

                                // Set out and length of file
                                mlt_properties_set_position( properties, "out", ( length * fps ) - 1 );
                                mlt_properties_set_position( properties, "length", ( length * fps ) );
                        }
                }
                else
                {
                        // Clean up
                        free( ov );

                        // Must close input file when open fails
                        fclose( input );
                }
        }

        return error;
}

/** Convert a frame position to a time code.
*/

static double producer_time_of_frame( mlt_producer this, mlt_position position )
{
        // Get the properties
        mlt_properties properties = mlt_producer_properties( this );

        // Obtain the fps
        double fps = mlt_properties_get_double( properties, "fps" );

        // Do the calc
        return ( double )position / fps;
}

/** Get the audio from a frame.
*/

static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
{
        // Get the properties from the frame
        mlt_properties frame_properties = mlt_frame_properties( frame );

        // Obtain the frame number of this frame
        mlt_position position = mlt_properties_get_position( frame_properties, "vorbis_position" );

        // Get the producer 
        mlt_producer this = mlt_properties_get_data( frame_properties, "vorbis_producer", NULL );

        // Get the producer properties
        mlt_properties properties = mlt_producer_properties( this );

        // Get the ogg vorbis file
        OggVorbis_File *ov = mlt_properties_get_data( properties, "ogg_vorbis_file", NULL );

        // Obtain the expected frame numer
        mlt_position expected = mlt_properties_get_position( properties, "audio_expected" );

        // Get the fps for this producer
        double fps = mlt_properties_get_double( properties, "fps" );

        // Get the vorbis info
        vorbis_info *vi = ov_info( ov, -1 );

        // Obtain the audio buffer
        int16_t *audio_buffer = mlt_properties_get_data( properties, "audio_buffer", NULL );

        // Get amount of audio used
        int audio_used =  mlt_properties_get_int( properties, "audio_used" );

        // Number of frames to ignore (for ffwd)
        int ignore = 0;

        // Flag for paused (silence) 
        int paused = 0;

        // Check for audio buffer and create if necessary
        if ( audio_buffer == NULL )
        {
                // Allocate the audio buffer
                audio_buffer = mlt_pool_alloc( 131072 * sizeof( int16_t ) );

                // And store it on properties for reuse
                mlt_properties_set_data( properties, "audio_buffer", audio_buffer, 0, mlt_pool_release, NULL );
        }

        // Seek if necessary
        if ( position != expected )
        {
                if ( position + 1 == expected )
                {
                        // We're paused - silence required
                        paused = 1;
                }
                else if ( position > expected && ( position - expected ) < 250 )
                {
                        // Fast forward - seeking is inefficient for small distances - just ignore following frames
                        ignore = position - expected;
                }
                else
                {
                        // Seek to the required position
                        ov_time_seek( ov, producer_time_of_frame( this, position ) );
                        expected = position;
                        audio_used = 0;
                }
        }

        // Return info in frame
        *frequency = vi->rate;
        *channels = vi->channels;

        // Get the audio if required
        if ( !paused )
        {
                // Bitstream section
                int current_section;

                // Get the number of samples for the current frame
                *samples = mlt_sample_calculator( fps, *frequency, expected ++ );

                while( *samples > audio_used  )
                {
                        // Read the samples
                        int bytes = ov_read( ov, ( char * )( &audio_buffer[ audio_used * 2 ] ), 4096, 0, 2, 1, &current_section );

                        // Break if error or eof
                        if ( bytes <= 0 )
                                break;

                        // Increment number of samples used
                        audio_used += bytes / ( sizeof( int16_t ) * *channels );

                        // Handle ignore
                        while ( ignore && audio_used >= *samples )
                        {
                                ignore --;
                                audio_used -= *samples;
                                memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * sizeof( int16_t ) );
                                *samples = mlt_sample_calculator( fps, *frequency, expected ++ );
                        }
                }

                // Now handle the audio if we have enough
                if ( audio_used >= *samples )
                {
                        *buffer = mlt_pool_alloc( *samples * *channels * sizeof( int16_t ) );
                        memcpy( *buffer, audio_buffer, *samples * *channels * sizeof( int16_t ) );
                        audio_used -= *samples;
                        memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * *channels * sizeof( int16_t ) );
                        mlt_properties_set_data( frame_properties, "audio", *buffer, 0, mlt_pool_release, NULL );
                }
                else
                {
                        frame->get_audio = NULL;
                        mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
                        audio_used = 0;
                }
                
                // Store the number of audio samples still available
                mlt_properties_set_int( properties, "audio_used", audio_used );
        }
        else
        {
                // Get silence and don't touch the context
                frame->get_audio = NULL;
                *samples = mlt_sample_calculator( fps, *frequency, position );
                mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
        }

        // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
        mlt_properties_set_position( properties, "audio_expected", position + 1 );

        return 0;
}

/** Set up audio handling.
*/

static void producer_set_up_audio( mlt_producer this, mlt_frame frame )
{
        // Get the properties
        mlt_properties properties = mlt_frame_properties( frame );

        // Set the audio method
        frame->get_audio = producer_get_audio;

        // Set the producer on the frame
        mlt_properties_set_data( properties, "vorbis_producer", this, 0, NULL, NULL );
}

/** Our get frame implementation.
*/

static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
{
        // Create an empty frame
        *frame = mlt_frame_init( );

        // Update timecode on the frame we're creating
        mlt_frame_set_position( *frame, mlt_producer_position( this ) );

        // Set the position of this producer
        mlt_properties_set_position( mlt_frame_properties( *frame ), "vorbis_position", mlt_producer_get_in( this ) + mlt_producer_position( this ) );

        // Set up the audio
        producer_set_up_audio( this, *frame );

        // Calculate the next timecode
        mlt_producer_prepare_next( this );

        return 0;
}