chromium/third_party/blink/renderer/modules/webcodecs/decoder_selector.cc

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/modules/webcodecs/decoder_selector.h"

#include "base/check_op.h"
#include "base/functional/bind.h"
#include "base/notreached.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/single_thread_task_runner.h"
#include "media/base/channel_layout.h"
#include "media/base/demuxer_stream.h"
#include "media/base/sample_format.h"
#include "media/filters/decrypting_demuxer_stream.h"
#include "third_party/blink/renderer/modules/modules_export.h"
#include "third_party/blink/renderer/platform/wtf/functional.h"

namespace blink {

// Demuxing isn't part of WebCodecs. This shim allows us to reuse decoder
// selection logic from <video>.
// TODO(chcunningham): Maybe refactor DecoderSelector to separate dependency on
// media::DemuxerStream. DecoderSelection doesn't conceptually require a
// Demuxer. The tough part is re-working Decryptingmedia::DemuxerStream.
template <media::DemuxerStream::Type StreamType>
class NullDemuxerStream : public media::DemuxerStream { … };

template <>
void NullDemuxerStream<media::DemuxerStream::AUDIO>::Configure(
    DecoderConfigType config) { … }

template <>
void NullDemuxerStream<media::DemuxerStream::VIDEO>::Configure(
    DecoderConfigType config) { … }

template <media::DemuxerStream::Type StreamType>
DecoderSelector<StreamType>::DecoderSelector(
    scoped_refptr<base::SequencedTaskRunner> task_runner,
    CreateDecodersCB create_decoders_cb,
    typename Decoder::OutputCB output_cb)
    : … { … }

template <media::DemuxerStream::Type StreamType>
DecoderSelector<StreamType>::~DecoderSelector() = default;

template <media::DemuxerStream::Type StreamType>
void DecoderSelector<StreamType>::SelectDecoder(
    const DecoderConfig& config,
    bool low_delay,
    SelectDecoderCB select_decoder_cb) { … }

template <>
std::unique_ptr<WebCodecsAudioDecoderSelector::StreamTraits>
DecoderSelector<media::DemuxerStream::AUDIO>::CreateStreamTraits() { … }

template <>
std::unique_ptr<WebCodecsVideoDecoderSelector::StreamTraits>
DecoderSelector<media::DemuxerStream::VIDEO>::CreateStreamTraits() { … }

template <media::DemuxerStream::Type StreamType>
void DecoderSelector<StreamType>::OnDecoderSelected(
    SelectDecoderCB select_decoder_cb,
    DecoderOrError decoder_or_error,
    std::unique_ptr<media::DecryptingDemuxerStream> decrypting_demuxer_stream) { … }

template class MODULES_EXPORT DecoderSelector<media::DemuxerStream::VIDEO>;
template class MODULES_EXPORT DecoderSelector<media::DemuxerStream::AUDIO>;

}  // namespace blink