87 lines
3.1 KiB
C++
87 lines
3.1 KiB
C++
/***
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Olive - Non-Linear Video Editor
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Copyright (C) 2022 Olive Team
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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***/
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#ifndef AUDIOPLAYBACKCACHE_H
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#define AUDIOPLAYBACKCACHE_H
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#include "audio/audiovisualwaveform.h"
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#include "common/timerange.h"
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#include "codec/samplebuffer.h"
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#include "render/playbackcache.h"
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namespace olive {
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/**
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* @brief A fully integrated system of storing and playing cached audio
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*
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* All audio in Olive is processed and rendered in advance. This makes playback extremely smooth
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* and reliable, but provides some challenges as far as storing and manipulating this audio while
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* minimizing the amount of re-renders necessary.
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*
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* Olive's PlaybackCaches support "shifting"; moving cached data to a different spot on the
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* timeline without requiring a costly re-render. While video is naturally stored on disk as
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* separate frames that are easy to swap out, audio works a little differently. It would be
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* extremely inefficient to store each sample as a separate file on the disk, but storing in
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* one single contiguous file would be detrimental to shifting, particularly for longer timelines
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* since the data will actually have to be shifted on disk.
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*
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* As such, AudioPlaybackCache compromises by storing audio in several "segments". This makes
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* operations like shifting much easier since segments can simply be removed from the playlist
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* rather than having to shift or re-render potentially hours of audio in every operation.
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*
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* Naturally, storing in segments means you can't simply play the PCM data like a file, so
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* AudioPlaybackCache also provides a playback device (accessible from CreatePlaybackDevice()) that
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* acts identically to a file-based IO device, transparently joining segments together and acting
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* like one contiguous file.
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*/
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class AudioPlaybackCache : public PlaybackCache
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{
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Q_OBJECT
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public:
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AudioPlaybackCache(QObject* parent = nullptr);
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virtual ~AudioPlaybackCache() override;
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AudioParams GetParameters()
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{
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return params_;
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}
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void SetParameters(const AudioParams& params);
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void WritePCM(const TimeRange &range, const TimeRangeList &valid_ranges, const SampleBuffer &samples);
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void WriteSilence(const TimeRange &range);
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private:
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bool WritePartOfSampleBuffer(const SampleBuffer &samples, const rational &write_start, const rational &buffer_start, const rational &length);
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QString GetSegmentFilename(qint64 segment_index, int channel);
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static const qint64 kDefaultSegmentSizePerChannel;
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AudioParams params_;
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};
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}
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#endif // AUDIOPLAYBACKCACHE_H
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