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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Implements the Demuxer interface using FFmpeg's libavformat. At this time
// will support demuxing any audio/video format thrown at it. The streams
// output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
// key FFmpegCodecID which contains the CodecID enumeration value. The CodecIDs
// can be used to create and initialize the corresponding FFmpeg decoder.
//
// FFmpegDemuxer sets the duration of pipeline during initialization by using
// the duration of the longest audio/video stream.
//
// NOTE: since FFmpegDemuxer reads packets sequentially without seeking, media
// files with very large drift between audio/video streams may result in
// excessive memory consumption.
//
// When stopped, FFmpegDemuxer and FFmpegDemuxerStream release all callbacks
// and buffered packets. Reads from a stopped FFmpegDemuxerStream will not be
// replied to.
#ifndef MEDIA_FILTERS_FFMPEG_DEMUXER_H_
#define MEDIA_FILTERS_FFMPEG_DEMUXER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "base/callback.h"
#include "base/macros.h"
#include "base/threading/thread.h"
#include "media/base/audio_decoder_config.h"
#include "media/base/decoder_buffer.h"
#include "media/base/decoder_buffer_queue.h"
#include "media/base/demuxer.h"
#include "media/base/pipeline_status.h"
#include "media/base/text_track_config.h"
#include "media/base/video_decoder_config.h"
#include "media/ffmpeg/ffmpeg_deleters.h"
#include "media/filters/blocking_url_protocol.h"
#include "media/media_features.h"
// FFmpeg forward declarations.
struct AVFormatContext;
struct AVPacket;
struct AVRational;
struct AVStream;
namespace media {
class MediaLog;
class FFmpegBitstreamConverter;
class FFmpegDemuxer;
class FFmpegGlue;
typedef std::unique_ptr<AVPacket, ScopedPtrAVFreePacket> ScopedAVPacket;
class MEDIA_EXPORT FFmpegDemuxerStream : public DemuxerStream {
public:
// Attempts to create FFmpegDemuxerStream form the given AVStream. Will return
// null if the AVStream cannot be translated into a valid decoder config.
//
// FFmpegDemuxerStream keeps a copy of |demuxer| and initializes itself using
// information inside |stream|. Both parameters must outlive |this|.
static std::unique_ptr<FFmpegDemuxerStream> Create(
FFmpegDemuxer* demuxer,
AVStream* stream,
const scoped_refptr<MediaLog>& media_log);
~FFmpegDemuxerStream() override;
// Enqueues the given AVPacket. It is invalid to queue a |packet| after
// SetEndOfStream() has been called.
void EnqueuePacket(ScopedAVPacket packet);
// Enters the end of stream state. After delivering remaining queued buffers
// only end of stream buffers will be delivered.
void SetEndOfStream();
// Drops queued buffers and clears end of stream state.
void FlushBuffers();
// Empties the queues and ignores any additional calls to Read().
void Stop();
// Aborts any pending reads.
void Abort();
base::TimeDelta duration() const { return duration_; }
// Enables fixes for files with negative timestamps. Normally all timestamps
// are rebased against FFmpegDemuxer::start_time() whenever that value is
// negative. When this fix is enabled, only AUDIO stream packets will be
// rebased to time zero, all other stream types will use the muxed timestamp.
//
// Further, when no codec delay is present, all AUDIO packets which originally
// had negative timestamps will be marked for post-decode discard. When codec
// delay is present, it is assumed the decoder will handle discard and does
// not need the AUDIO packets to be marked for discard; just rebased to zero.
void enable_negative_timestamp_fixups() {
fixup_negative_timestamps_ = true;
}
// DemuxerStream implementation.
Type type() const override;
Liveness liveness() const override;
void Read(const ReadCB& read_cb) override;
void EnableBitstreamConverter() override;
bool SupportsConfigChanges() override;
AudioDecoderConfig audio_decoder_config() override;
VideoDecoderConfig video_decoder_config() override;
VideoRotation video_rotation() override;
bool enabled() const;
void set_enabled(bool enabled, base::TimeDelta timestamp);
void SetStreamStatusChangeCB(const StreamStatusChangeCB& cb);
void SetLiveness(Liveness liveness);
// Returns the range of buffered data in this stream.
Ranges<base::TimeDelta> GetBufferedRanges() const;
// Returns true if this stream has capacity for additional data.
bool HasAvailableCapacity();
// Returns the total buffer size FFMpegDemuxerStream is holding onto.
size_t MemoryUsage() const;
TextKind GetTextKind() const;
// Returns the value associated with |key| in the metadata for the avstream.
// Returns an empty string if the key is not present.
std::string GetMetadata(const char* key) const;
AVStream* av_stream() const { return stream_; }
base::TimeDelta start_time() const { return start_time_; }
void set_start_time(base::TimeDelta time) { start_time_ = time; }
private:
friend class FFmpegDemuxerTest;
// Use FFmpegDemuxerStream::Create to construct.
// Audio/Video streams must include their respective DecoderConfig. At most
// one DecoderConfig should be provided (leaving the other nullptr). Both
// configs should be null for text streams.
FFmpegDemuxerStream(FFmpegDemuxer* demuxer,
AVStream* stream,
std::unique_ptr<AudioDecoderConfig> audio_config,
std::unique_ptr<VideoDecoderConfig> video_config);
// Runs |read_cb_| if present with the front of |buffer_queue_|, calling
// NotifyCapacityAvailable() if capacity is still available.
void SatisfyPendingRead();
// Converts an FFmpeg stream timestamp into a base::TimeDelta.
static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
int64_t timestamp);
// Resets any currently active bitstream converter.
void ResetBitstreamConverter();
// Create new bitstream converter, destroying active converter if present.
void InitBitstreamConverter();
FFmpegDemuxer* demuxer_;
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
AVStream* stream_;
base::TimeDelta start_time_;
std::unique_ptr<AudioDecoderConfig> audio_config_;
std::unique_ptr<VideoDecoderConfig> video_config_;
Type type_;
Liveness liveness_;
base::TimeDelta duration_;
bool end_of_stream_;
base::TimeDelta last_packet_timestamp_;
base::TimeDelta last_packet_duration_;
Ranges<base::TimeDelta> buffered_ranges_;
VideoRotation video_rotation_;
bool is_enabled_;
bool waiting_for_keyframe_;
bool aborted_;
DecoderBufferQueue buffer_queue_;
ReadCB read_cb_;
StreamStatusChangeCB stream_status_change_cb_;
#if BUILDFLAG(USE_PROPRIETARY_CODECS)
std::unique_ptr<FFmpegBitstreamConverter> bitstream_converter_;
#endif
std::string encryption_key_id_;
bool fixup_negative_timestamps_;
DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxerStream);
};
class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
public:
FFmpegDemuxer(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
DataSource* data_source,
const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
const MediaTracksUpdatedCB& media_tracks_updated_cb,
const scoped_refptr<MediaLog>& media_log);
~FFmpegDemuxer() override;
// Demuxer implementation.
std::string GetDisplayName() const override;
void Initialize(DemuxerHost* host,
const PipelineStatusCB& status_cb,
bool enable_text_tracks) override;
void AbortPendingReads() override;
void Stop() override;
void StartWaitingForSeek(base::TimeDelta seek_time) override;
void CancelPendingSeek(base::TimeDelta seek_time) override;
void Seek(base::TimeDelta time, const PipelineStatusCB& cb) override;
base::Time GetTimelineOffset() const override;
std::vector<DemuxerStream*> GetAllStreams() override;
void SetStreamStatusChangeCB(const StreamStatusChangeCB& cb) override;
base::TimeDelta GetStartTime() const override;
int64_t GetMemoryUsage() const override;
// Calls |encrypted_media_init_data_cb_| with the initialization data
// encountered in the file.
void OnEncryptedMediaInitData(EmeInitDataType init_data_type,
const std::string& encryption_key_id);
// Allow FFmpegDemuxerStream to notify us when there is updated information
// about capacity and what buffered data is available.
void NotifyCapacityAvailable();
void NotifyBufferingChanged();
// Allow FFmpegDemxuerStream to notify us about an error.
void NotifyDemuxerError(PipelineStatus error);
void OnEnabledAudioTracksChanged(const std::vector<MediaTrack::Id>& track_ids,
base::TimeDelta currTime) override;
// |track_ids| is either empty or contains a single video track id.
void OnSelectedVideoTrackChanged(const std::vector<MediaTrack::Id>& track_ids,
base::TimeDelta currTime) override;
// The lowest demuxed timestamp. If negative, DemuxerStreams must use this to
// adjust packet timestamps such that external clients see a zero-based
// timeline.
base::TimeDelta start_time() const { return start_time_; }
private:
// To allow tests access to privates.
friend class FFmpegDemuxerTest;
// FFmpeg callbacks during initialization.
void OnOpenContextDone(const PipelineStatusCB& status_cb, bool result);
void OnFindStreamInfoDone(const PipelineStatusCB& status_cb, int result);
void LogMetadata(AVFormatContext* avctx, base::TimeDelta max_duration);
// FFmpeg callbacks during seeking.
void OnSeekFrameDone(int result);
// FFmpeg callbacks during reading + helper method to initiate reads.
void ReadFrameIfNeeded();
void OnReadFrameDone(ScopedAVPacket packet, int result);
// Returns true iff any stream has additional capacity. Note that streams can
// go over capacity depending on how the file is muxed.
bool StreamsHaveAvailableCapacity();
// Returns true if the maximum allowed memory usage has been reached.
bool IsMaxMemoryUsageReached() const;
// Signal all FFmpegDemuxerStreams that the stream has ended.
void StreamHasEnded();
// Called by |url_protocol_| whenever |data_source_| returns a read error.
void OnDataSourceError();
// Returns the first stream from |streams_| that matches |type| as an
// FFmpegDemuxerStream and is enabled.
FFmpegDemuxerStream* GetFirstEnabledFFmpegStream(
DemuxerStream::Type type) const;
// Called after the streams have been collected from the media, to allow
// the text renderer to bind each text stream to the cue rendering engine.
void AddTextStreams();
void SetLiveness(DemuxerStream::Liveness liveness);
DemuxerHost* host_;
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// Thread on which all blocking FFmpeg operations are executed.
base::Thread blocking_thread_;
// Tracks if there's an outstanding av_read_frame() operation.
//
// TODO(scherkus): Allow more than one read in flight for higher read
// throughput using demuxer_bench to verify improvements.
bool pending_read_;
// Tracks if there's an outstanding av_seek_frame() operation. Used to discard
// results of pre-seek av_read_frame() operations.
PipelineStatusCB pending_seek_cb_;
// |streams_| mirrors the AVStream array in AVFormatContext. It contains
// FFmpegDemuxerStreams encapsluating AVStream objects at the same index.
//
// Since we only support a single audio and video stream, |streams_| will
// contain NULL entries for additional audio/video streams as well as for
// stream types that we do not currently support.
//
// Once initialized, operations on FFmpegDemuxerStreams should be carried out
// on the demuxer thread.
using StreamVector = std::vector<std::unique_ptr<FFmpegDemuxerStream>>;
StreamVector streams_;
// Provides asynchronous IO to this demuxer. Consumed by |url_protocol_| to
// integrate with libavformat.
DataSource* data_source_;
scoped_refptr<MediaLog> media_log_;
// Derived bitrate after initialization has completed.
int bitrate_;
// The first timestamp of the audio or video stream, whichever is lower. This
// is used to adjust timestamps so that external consumers always see a zero
// based timeline.
base::TimeDelta start_time_;
// Finds the stream with the lowest known start time (i.e. not kNoTimestamp
// start time) with enabled status matching |enabled|.
FFmpegDemuxerStream* FindStreamWithLowestStartTimestamp(bool enabled);
// Finds a preferred stream for seeking to |seek_time|. Preference is
// typically given to video streams, unless the |seek_time| is earlier than
// the start time of the video stream. In that case a stream with the earliest
// start time is preferred. Disabled streams are considered only as the last
// fallback option.
FFmpegDemuxerStream* FindPreferredStreamForSeeking(base::TimeDelta seek_time);
// The Time associated with timestamp 0. Set to a null
// time if the file doesn't have an association to Time.
base::Time timeline_offset_;
// Whether text streams have been enabled for this demuxer.
bool text_enabled_;
// Set if we know duration of the audio stream. Used when processing end of
// stream -- at this moment we definitely know duration.
bool duration_known_;
base::TimeDelta duration_;
// FFmpegURLProtocol implementation and corresponding glue bits.
std::unique_ptr<BlockingUrlProtocol> url_protocol_;
std::unique_ptr<FFmpegGlue> glue_;
const EncryptedMediaInitDataCB encrypted_media_init_data_cb_;
const MediaTracksUpdatedCB media_tracks_updated_cb_;
std::map<MediaTrack::Id, FFmpegDemuxerStream*> track_id_to_demux_stream_map_;
// NOTE: Weak pointers must be invalidated before all other member variables.
base::WeakPtr<FFmpegDemuxer> weak_this_;
base::WeakPtrFactory<FFmpegDemuxer> cancel_pending_seek_factory_;
base::WeakPtrFactory<FFmpegDemuxer> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
};
} // namespace media
#endif // MEDIA_FILTERS_FFMPEG_DEMUXER_H_