shaka-packager/packager/media/formats/webm/webm_media_parser.cc

267 lines
7.1 KiB
C++

// Copyright 2014 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.
#include "packager/media/formats/webm/webm_media_parser.h"
#include <string>
#include <glog/logging.h>
#include "packager/media/base/buffer_writer.h"
#include "packager/media/base/timestamp.h"
#include "packager/media/formats/webm/webm_cluster_parser.h"
#include "packager/media/formats/webm/webm_constants.h"
#include "packager/media/formats/webm/webm_content_encodings.h"
#include "packager/media/formats/webm/webm_info_parser.h"
#include "packager/media/formats/webm/webm_tracks_parser.h"
namespace shaka {
namespace media {
WebMMediaParser::WebMMediaParser()
: state_(kWaitingForInit), unknown_segment_size_(false) {}
WebMMediaParser::~WebMMediaParser() {}
void WebMMediaParser::Init(const InitCB& init_cb,
const NewMediaSampleCB& new_media_sample_cb,
const NewTextSampleCB&,
KeySource* decryption_key_source) {
DCHECK_EQ(state_, kWaitingForInit);
DCHECK(!init_cb_);
DCHECK(init_cb);
DCHECK(new_media_sample_cb);
ChangeState(kParsingHeaders);
init_cb_ = init_cb;
new_sample_cb_ = new_media_sample_cb;
decryption_key_source_ = decryption_key_source;
ignore_text_tracks_ = true;
}
bool WebMMediaParser::Flush() {
DCHECK_NE(state_, kWaitingForInit);
byte_queue_.Reset();
bool result = true;
if (cluster_parser_)
result = cluster_parser_->Flush();
if (state_ == kParsingClusters) {
ChangeState(kParsingHeaders);
}
return result;
}
bool WebMMediaParser::Parse(const uint8_t* buf, int size) {
DCHECK_NE(state_, kWaitingForInit);
if (state_ == kError)
return false;
byte_queue_.Push(buf, size);
int result = 0;
int bytes_parsed = 0;
const uint8_t* cur = NULL;
int cur_size = 0;
byte_queue_.Peek(&cur, &cur_size);
while (cur_size > 0) {
State oldState = state_;
switch (state_) {
case kParsingHeaders:
result = ParseInfoAndTracks(cur, cur_size);
break;
case kParsingClusters:
result = ParseCluster(cur, cur_size);
break;
case kWaitingForInit:
case kError:
return false;
}
if (result < 0) {
ChangeState(kError);
return false;
}
if (state_ == oldState && result == 0)
break;
DCHECK_GE(result, 0);
cur += result;
cur_size -= result;
bytes_parsed += result;
}
byte_queue_.Pop(bytes_parsed);
return true;
}
void WebMMediaParser::ChangeState(State new_state) {
DVLOG(1) << "ChangeState() : " << state_ << " -> " << new_state;
state_ = new_state;
}
int WebMMediaParser::ParseInfoAndTracks(const uint8_t* data, int size) {
DVLOG(2) << "ParseInfoAndTracks()";
DCHECK(data);
DCHECK_GT(size, 0);
const uint8_t* cur = data;
int cur_size = size;
int bytes_parsed = 0;
int id;
int64_t element_size;
int result = WebMParseElementHeader(cur, cur_size, &id, &element_size);
if (result <= 0)
return result;
switch (id) {
case kWebMIdEBMLHeader:
case kWebMIdSeekHead:
case kWebMIdVoid:
case kWebMIdCRC32:
case kWebMIdCues:
case kWebMIdChapters:
case kWebMIdTags:
case kWebMIdAttachments:
// TODO: Implement support for chapters.
if (cur_size < (result + element_size)) {
// We don't have the whole element yet. Signal we need more data.
return 0;
}
// Skip the element.
return result + element_size;
break;
case kWebMIdCluster:
if (!cluster_parser_) {
LOG(ERROR) << "Found Cluster element before Info.";
return -1;
}
ChangeState(kParsingClusters);
return 0;
break;
case kWebMIdSegment:
// Segment of unknown size indicates live stream.
if (element_size == kWebMUnknownSize)
unknown_segment_size_ = true;
// Just consume the segment header.
return result;
break;
case kWebMIdInfo:
// We've found the element we are looking for.
break;
default: {
LOG(ERROR) << "Unexpected element ID 0x" << std::hex << id;
return -1;
}
}
WebMInfoParser info_parser;
result = info_parser.Parse(cur, cur_size);
if (result <= 0)
return result;
cur += result;
cur_size -= result;
bytes_parsed += result;
WebMTracksParser tracks_parser(ignore_text_tracks_);
result = tracks_parser.Parse(cur, cur_size);
if (result <= 0)
return result;
bytes_parsed += result;
double timecode_scale_in_us = info_parser.timecode_scale() / 1000.0;
int64_t duration_in_us = info_parser.duration() * timecode_scale_in_us;
std::shared_ptr<AudioStreamInfo> audio_stream_info =
tracks_parser.audio_stream_info();
if (audio_stream_info) {
audio_stream_info->set_duration(duration_in_us);
} else {
VLOG(1) << "No audio track info found.";
}
std::shared_ptr<VideoStreamInfo> video_stream_info =
tracks_parser.video_stream_info();
if (video_stream_info) {
video_stream_info->set_duration(duration_in_us);
} else {
VLOG(1) << "No video track info found.";
}
if (!FetchKeysIfNecessary(tracks_parser.audio_encryption_key_id(),
tracks_parser.video_encryption_key_id())) {
return -1;
}
cluster_parser_.reset(new WebMClusterParser(
info_parser.timecode_scale(), audio_stream_info, video_stream_info,
tracks_parser.vp_config(),
tracks_parser.GetAudioDefaultDuration(timecode_scale_in_us),
tracks_parser.GetVideoDefaultDuration(timecode_scale_in_us),
tracks_parser.text_tracks(), tracks_parser.ignored_tracks(),
tracks_parser.audio_encryption_key_id(),
tracks_parser.video_encryption_key_id(), new_sample_cb_, init_cb_,
decryption_key_source_));
return bytes_parsed;
}
int WebMMediaParser::ParseCluster(const uint8_t* data, int size) {
if (!cluster_parser_)
return -1;
int bytes_parsed = cluster_parser_->Parse(data, size);
if (bytes_parsed < 0)
return bytes_parsed;
bool cluster_ended = cluster_parser_->cluster_ended();
if (cluster_ended) {
ChangeState(kParsingHeaders);
}
return bytes_parsed;
}
bool WebMMediaParser::FetchKeysIfNecessary(
const std::string& audio_encryption_key_id,
const std::string& video_encryption_key_id) {
if (audio_encryption_key_id.empty() && video_encryption_key_id.empty())
return true;
// An error will be returned later if the samples need to be decrypted.
if (!decryption_key_source_)
return true;
Status status;
if (!audio_encryption_key_id.empty()) {
status.Update(decryption_key_source_->FetchKeys(
EmeInitDataType::WEBM,
std::vector<uint8_t>(audio_encryption_key_id.begin(),
audio_encryption_key_id.end())));
}
if (!video_encryption_key_id.empty()) {
status.Update(decryption_key_source_->FetchKeys(
EmeInitDataType::WEBM,
std::vector<uint8_t>(video_encryption_key_id.begin(),
video_encryption_key_id.end())));
}
if (!status.ok()) {
LOG(ERROR) << "Error fetching decryption keys: " << status;
return false;
}
return true;
}
} // namespace media
} // namespace shaka