resampled_source.cc

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/*
    Copyright (C) 2007 Paul Davis

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include "pbd/error.h"
#include "ardour/resampled_source.h"
#include "pbd/failed_constructor.h"

#include "i18n.h"

using namespace ARDOUR;
using namespace PBD;

#ifdef PLATFORM_WINDOWS
const uint32_t ResampledImportableSource::blocksize = 524288U;
#else
const uint32_t ResampledImportableSource::blocksize = 16384U;
#endif

ResampledImportableSource::ResampledImportableSource (boost::shared_ptr<ImportableSource> src, framecnt_t rate, SrcQuality srcq)
        : source (src)
        , src_state (0)
{
        _src_type = SRC_SINC_BEST_QUALITY;

        switch (srcq) {
        case SrcBest:
                _src_type = SRC_SINC_BEST_QUALITY;
                break;
        case SrcGood:
                _src_type = SRC_SINC_MEDIUM_QUALITY;
                break;
        case SrcQuick:
                _src_type = SRC_SINC_FASTEST;
                break;
        case SrcFast:
                _src_type = SRC_ZERO_ORDER_HOLD;
                break;
        case SrcFastest:
                _src_type = SRC_LINEAR;
                break;
        }

        input = new float[blocksize];

        seek (0);

        src_data.src_ratio = ((float) rate) / source->samplerate();
}

ResampledImportableSource::~ResampledImportableSource ()
{
        src_state = src_delete (src_state) ;
        delete [] input;
}

framecnt_t
ResampledImportableSource::read (Sample* output, framecnt_t nframes)
{
        int err;

        /* If the input buffer is empty, refill it. */

        if (src_data.input_frames == 0) {

                src_data.input_frames = source->read (input, blocksize);

                /* The last read will not be a full buffer, so set end_of_input. */

                if ((framecnt_t) src_data.input_frames < blocksize) {
                        src_data.end_of_input = true;
                }

                src_data.input_frames /= source->channels();
                src_data.data_in = input;
        }

        src_data.data_out = output;

        if (!src_data.end_of_input) {
                src_data.output_frames = nframes / source->channels();
        } else {
                src_data.output_frames = std::min ((framecnt_t) src_data.input_frames, nframes / source->channels());
        }

        if ((err = src_process (src_state, &src_data))) {
                error << string_compose(_("Import: %1"), src_strerror (err)) << endmsg ;
                return 0 ;
        }

        /* Terminate if at end */

        if (src_data.end_of_input && src_data.output_frames_gen == 0) {
                return 0;
        }

        src_data.data_in += src_data.input_frames_used * source->channels();
        src_data.input_frames -= src_data.input_frames_used ;

        return src_data.output_frames_gen * source->channels();
}

void
ResampledImportableSource::seek (framepos_t pos)
{
        source->seek (pos);

        /* and reset things so that we start from scratch with the conversion */

        if (src_state) {
                src_delete (src_state);
        }

        int err;

        if ((src_state = src_new (_src_type, source->channels(), &err)) == 0) {
                error << string_compose(_("Import: src_new() failed : %1"), src_strerror (err)) << endmsg ;
                throw failed_constructor ();
        }

        src_data.input_frames = 0;
        src_data.data_in = input;
        src_data.end_of_input = 0;
}

framepos_t
ResampledImportableSource::natural_position () const
{
        return source->natural_position() * ratio ();
}