ffmpegfileimportable.h

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/*
 * Copyright (C) 2021 Marijn Kruisselbrink <mek@google.com>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#ifndef _ardour_ffmpegfile_importable_source_h_
#define _ardour_ffmpegfile_importable_source_h_
 
#include <atomic>
 
#include "pbd/ringbuffer.h"
 
#include "ardour/importable_source.h"
#include "ardour/libardour_visibility.h"
#include "ardour/system_exec.h"
#include "ardour/types.h"
 
namespace ARDOUR {
 
class LIBARDOUR_API FFMPEGFileImportableSource : public ImportableSource
{
public:
        enum {
                ALL_CHANNELS = -1,
        };
 
        FFMPEGFileImportableSource (const std::string& path, int channel = ALL_CHANNELS);
 
        virtual ~FFMPEGFileImportableSource ();
 
        /* ImportableSource API */
        samplecnt_t read (Sample*, samplecnt_t nframes);
        uint32_t    channels () const { return _channels; }
        samplecnt_t length () const { return _length; }
        samplecnt_t samplerate () const { return _samplerate; }
        void        seek (samplepos_t pos);
        samplepos_t natural_position () const { return _natural_position; }
        bool        clamped_at_unity () const { return false; }
 
        std::string format_name () const { return _format_name; }
 
private:
        void start_ffmpeg ();
        void reset ();
 
        void did_read_data (std::string data, size_t size);
 
        std::string _path;
        int         _channel;
 
        uint32_t    _channels;
        samplecnt_t _length;
        samplecnt_t _samplerate;
        samplepos_t _natural_position;
        std::string _format_name;
 
        PBD::RingBuffer<Sample> _buffer;
        /* Set to 1 to indicate that ffmpeg should be terminating. */
        std::atomic<int> _ffmpeg_should_terminate;
 
        /* To make sure we don't try to parse partial floats, we might have a couple of bytes
         * of leftover unparsable data after any `did_read_data` call. Those couple of bytes are
         * stored here until the next `did_read_data` call.
         */
        std::string _leftover_data;
 
        samplecnt_t _read_pos;
 
        ARDOUR::SystemExec*   _ffmpeg_exec;
        PBD::ScopedConnection _ffmpeg_conn;
};
 
} // namespace ARDOUR
 
#endif /* _ardour_ffmpegfile_importable_source_h_ */