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shaka-packager/packager/media/formats/mp4/mp4_muxer.cc

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// Copyright 2014 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#include <packager/media/formats/mp4/mp4_muxer.h>
#include <algorithm>
#include <chrono>
#include <absl/log/check.h>
#include <absl/strings/escaping.h>
#include <absl/strings/numbers.h>
#include <packager/file.h>
#include <packager/macros/logging.h>
#include <packager/macros/status.h>
#include <packager/media/base/aes_encryptor.h>
#include <packager/media/base/audio_stream_info.h>
#include <packager/media/base/fourccs.h>
#include <packager/media/base/key_source.h>
#include <packager/media/base/media_sample.h>
#include <packager/media/base/text_stream_info.h>
#include <packager/media/base/video_stream_info.h>
#include <packager/media/codecs/es_descriptor.h>
#include <packager/media/event/muxer_listener.h>
#include <packager/media/formats/mp4/box_definitions.h>
#include <packager/media/formats/mp4/low_latency_segment_segmenter.h>
#include <packager/media/formats/mp4/multi_segment_segmenter.h>
#include <packager/media/formats/mp4/single_segment_segmenter.h>
#include <packager/media/formats/ttml/ttml_generator.h>
namespace shaka {
namespace media {
namespace mp4 {
namespace {
// Sets the range start and end value from offset and size.
// |start| and |end| are for byte-range-spec specified in RFC2616.
void SetStartAndEndFromOffsetAndSize(size_t offset,
size_t size,
Range* range) {
DCHECK(range);
range->start = static_cast<uint32_t>(offset);
// Note that ranges are inclusive. So we need - 1.
range->end = range->start + static_cast<uint32_t>(size) - 1;
}
FourCC CodecToFourCC(Codec codec, H26xStreamFormat h26x_stream_format) {
switch (codec) {
case kCodecAV1:
return FOURCC_av01;
case kCodecH264:
return h26x_stream_format ==
H26xStreamFormat::kNalUnitStreamWithParameterSetNalus
? FOURCC_avc3
: FOURCC_avc1;
case kCodecH265:
return h26x_stream_format ==
H26xStreamFormat::kNalUnitStreamWithParameterSetNalus
? FOURCC_hev1
: FOURCC_hvc1;
case kCodecH265DolbyVision:
return h26x_stream_format ==
H26xStreamFormat::kNalUnitStreamWithParameterSetNalus
? FOURCC_dvhe
: FOURCC_dvh1;
case kCodecVP8:
return FOURCC_vp08;
case kCodecVP9:
return FOURCC_vp09;
case kCodecAAC:
case kCodecMP3:
return FOURCC_mp4a;
case kCodecAC3:
return FOURCC_ac_3;
case kCodecALAC:
return FOURCC_alac;
case kCodecDTSC:
return FOURCC_dtsc;
case kCodecDTSH:
return FOURCC_dtsh;
case kCodecDTSL:
return FOURCC_dtsl;
case kCodecDTSE:
return FOURCC_dtse;
case kCodecDTSM:
return FOURCC_dtsm;
case kCodecDTSX:
return FOURCC_dtsx;
case kCodecEAC3:
return FOURCC_ec_3;
case kCodecAC4:
return FOURCC_ac_4;
case kCodecFlac:
return FOURCC_fLaC;
case kCodecOpus:
return FOURCC_Opus;
case kCodecIAMF:
return FOURCC_iamf;
case kCodecMha1:
return FOURCC_mha1;
case kCodecMhm1:
return FOURCC_mhm1;
default:
return FOURCC_NULL;
}
}
void GenerateSinf(FourCC old_type,
const EncryptionConfig& encryption_config,
ProtectionSchemeInfo* sinf) {
sinf->format.format = old_type;
DCHECK_NE(encryption_config.protection_scheme, FOURCC_NULL);
sinf->type.type = encryption_config.protection_scheme;
// The version of cenc implemented here. CENC 4.
const int kCencSchemeVersion = 0x00010000;
sinf->type.version = kCencSchemeVersion;
auto& track_encryption = sinf->info.track_encryption;
track_encryption.default_is_protected = 1;
track_encryption.default_crypt_byte_block =
encryption_config.crypt_byte_block;
track_encryption.default_skip_byte_block = encryption_config.skip_byte_block;
switch (encryption_config.protection_scheme) {
case FOURCC_cenc:
case FOURCC_cbc1:
DCHECK_EQ(track_encryption.default_crypt_byte_block, 0u);
DCHECK_EQ(track_encryption.default_skip_byte_block, 0u);
// CENCv3 10.1 ‘cenc’ AES-CTR scheme and 10.2 ‘cbc1’ AES-CBC scheme:
// The version of the Track Encryption Box (‘tenc’) SHALL be 0.
track_encryption.version = 0;
break;
case FOURCC_cbcs:
case FOURCC_cens:
// CENCv3 10.3 ‘cens’ AES-CTR subsample pattern encryption scheme and
// 10.4 ‘cbcs’ AES-CBC subsample pattern encryption scheme:
// The version of the Track Encryption Box (‘tenc’) SHALL be 1.
track_encryption.version = 1;
break;
default:
NOTIMPLEMENTED() << "Unexpected protection scheme "
<< encryption_config.protection_scheme;
}
track_encryption.default_per_sample_iv_size =
encryption_config.per_sample_iv_size;
track_encryption.default_constant_iv = encryption_config.constant_iv;
track_encryption.default_kid = encryption_config.key_id;
}
// The roll distance is expressed in sample units and always takes negative
// values.
int16_t GetRollDistance(uint64_t seek_preroll_ns, uint32_t sampling_frequency) {
const double kNanosecondsPerSecond = 1000000000;
const double preroll_in_samples =
seek_preroll_ns / kNanosecondsPerSecond * sampling_frequency;
// Round to closest integer.
return -static_cast<int16_t>(preroll_in_samples + 0.5);
}
} // namespace
MP4Muxer::MP4Muxer(const MuxerOptions& options) : Muxer(options) {}
MP4Muxer::~MP4Muxer() {}
Status MP4Muxer::InitializeMuxer() {
// Muxer will be delay-initialized after seeing the first sample.
to_be_initialized_ = true;
return Status::OK;
}
Status MP4Muxer::Finalize() {
// This happens on streams that are not initialized, i.e. not going through
// DelayInitializeMuxer, which can only happen if there are no samples from
// the stream.
if (!segmenter_) {
DCHECK(to_be_initialized_);
LOG(INFO) << "Skip stream '" << options().output_file_name
<< "' which does not contain any sample.";
return Status::OK;
}
Status segmenter_finalized = segmenter_->Finalize();
if (!segmenter_finalized.ok())
return segmenter_finalized;
FireOnMediaEndEvent();
LOG(INFO) << "MP4 file '" << options().output_file_name << "' finalized.";
return Status::OK;
}
Status MP4Muxer::AddMediaSample(size_t stream_id, const MediaSample& sample) {
if (to_be_initialized_) {
RETURN_IF_ERROR(UpdateEditListOffsetFromSample(sample));
RETURN_IF_ERROR(DelayInitializeMuxer());
to_be_initialized_ = false;
}
DCHECK(segmenter_);
return segmenter_->AddSample(stream_id, sample);
}
Status MP4Muxer::FinalizeSegment(size_t stream_id,
const SegmentInfo& segment_info) {
DCHECK(segmenter_);
VLOG(3) << "Finalizing " << (segment_info.is_subsegment ? "sub" : "")
<< "segment " << segment_info.start_timestamp << " duration "
<< segment_info.duration << " segment number "
<< segment_info.segment_number;
return segmenter_->FinalizeSegment(stream_id, segment_info);
}
Status MP4Muxer::DelayInitializeMuxer() {
DCHECK(!streams().empty());
std::unique_ptr<FileType> ftyp(new FileType);
std::unique_ptr<Movie> moov(new Movie);
ftyp->major_brand = FOURCC_mp41;
ftyp->compatible_brands.push_back(FOURCC_iso8);
ftyp->compatible_brands.push_back(FOURCC_isom);
ftyp->compatible_brands.push_back(FOURCC_mp41);
ftyp->compatible_brands.push_back(FOURCC_dash);
if (streams().size() == 1) {
FourCC codec_fourcc = FOURCC_NULL;
if (streams()[0]->stream_type() == kStreamVideo) {
codec_fourcc =
CodecToFourCC(streams()[0]->codec(),
static_cast<const VideoStreamInfo*>(streams()[0].get())
->h26x_stream_format());
if (codec_fourcc != FOURCC_NULL)
ftyp->compatible_brands.push_back(codec_fourcc);
// https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolby_vision_bitstreams_within_the_iso_base_media_file_format_dec2017.pdf
std::string codec_string =
static_cast<const VideoStreamInfo*>(streams()[0].get())
->codec_string();
std::string supplemental_codec_string =
static_cast<const VideoStreamInfo*>(streams()[0].get())
->supplemental_codec();
if (codec_string.find("dvh") != std::string::npos ||
supplemental_codec_string.find("dvh") != std::string::npos ||
codec_string.find("dav1") != std::string::npos ||
supplemental_codec_string.find("dav1") != std::string::npos)
ftyp->compatible_brands.push_back(FOURCC_dby1);
FourCC extra_brand =
static_cast<const VideoStreamInfo*>(streams()[0].get())
->compatible_brand();
if (extra_brand != FOURCC_NULL)
ftyp->compatible_brands.push_back(extra_brand);
}
// CMAF allows only one track/stream per file.
// CMAF requires single initialization switching for AVC3/HEV1, which is not
// supported yet.
if (codec_fourcc != FOURCC_avc3 && codec_fourcc != FOURCC_hev1)
ftyp->compatible_brands.push_back(FOURCC_cmfc);
if (streams()[0]->stream_type() == kStreamAudio) {
codec_fourcc =
CodecToFourCC(streams()[0]->codec(), H26xStreamFormat::kUnSpecified);
if (codec_fourcc == FOURCC_iamf)
ftyp->compatible_brands.push_back(FOURCC_iamf);
}
}
moov->header.creation_time = IsoTimeNow();
moov->header.modification_time = IsoTimeNow();
moov->header.next_track_id = static_cast<uint32_t>(streams().size()) + 1;
moov->tracks.resize(streams().size());
moov->extends.tracks.resize(streams().size());
// Initialize tracks.
for (uint32_t i = 0; i < streams().size(); ++i) {
const StreamInfo* stream = streams()[i].get();
Track& trak = moov->tracks[i];
trak.header.track_id = i + 1;
TrackExtends& trex = moov->extends.tracks[i];
trex.track_id = trak.header.track_id;
trex.default_sample_description_index = 1;
bool generate_trak_result = false;
switch (stream->stream_type()) {
case kStreamVideo:
generate_trak_result = GenerateVideoTrak(
static_cast<const VideoStreamInfo*>(stream), &trak);
break;
case kStreamAudio:
generate_trak_result = GenerateAudioTrak(
static_cast<const AudioStreamInfo*>(stream), &trak);
break;
case kStreamText:
generate_trak_result = GenerateTextTrak(
static_cast<const TextStreamInfo*>(stream), &trak);
break;
default:
NOTIMPLEMENTED() << "Not implemented for stream type: "
<< stream->stream_type();
}
if (!generate_trak_result)
return Status(error::MUXER_FAILURE, "Failed to generate trak.");
// Generate EditList if needed. See UpdateEditListOffsetFromSample() for
// more information.
if (edit_list_offset_.value() > 0) {
EditListEntry entry;
entry.media_time = edit_list_offset_.value();
entry.media_rate_integer = 1;
trak.edit.list.edits.push_back(entry);
}
if (stream->is_encrypted() && options().mp4_params.include_pssh_in_stream) {
moov->pssh.clear();
const auto& key_system_info = stream->encryption_config().key_system_info;
for (const ProtectionSystemSpecificInfo& system : key_system_info) {
if (system.psshs.empty())
continue;
ProtectionSystemSpecificHeader pssh;
pssh.raw_box = system.psshs;
moov->pssh.push_back(pssh);
}
}
}
if (options().segment_template.empty()) {
segmenter_.reset(new SingleSegmentSegmenter(options(), std::move(ftyp),
std::move(moov)));
} else if (options().mp4_params.low_latency_dash_mode) {
segmenter_.reset(new LowLatencySegmentSegmenter(options(), std::move(ftyp),
std::move(moov)));
} else {
segmenter_.reset(
new MultiSegmentSegmenter(options(), std::move(ftyp), std::move(moov)));
}
const Status segmenter_initialized =
segmenter_->Initialize(streams(), muxer_listener(), progress_listener());
if (!segmenter_initialized.ok())
return segmenter_initialized;
FireOnMediaStartEvent();
return Status::OK;
}
Status MP4Muxer::UpdateEditListOffsetFromSample(const MediaSample& sample) {
if (edit_list_offset_)
return Status::OK;
const int64_t pts = sample.pts();
const int64_t dts = sample.dts();
// An EditList entry is inserted if one of the below conditions occur [4]:
// (1) pts > dts for the first sample. Due to Chrome's dts bug [1], dts is
// used in buffered range API, while pts is used elsewhere (players,
// manifests, and Chrome's own appendWindow check etc.), this
// inconsistency creates various problems, including possible stalls
// during playback. Since Chrome adjusts pts only when seeing EditList
// [2], we can insert an EditList with the time equal to difference of pts
// and dts to make aligned buffered ranges using pts and dts. This
// effectively workarounds the dts bug. It is also recommended by ISO-BMFF
// specification [3].
// (2) pts == dts and with pts < 0. This happens for some audio codecs where a
// negative presentation timestamp signals that the sample is not supposed
// to be shown, i.e. for audio priming. EditList is needed to encode
// negative timestamps.
// [1] https://crbug.com/718641, fixed but behind MseBufferByPts, still not
// enabled as of M67.
// [2] This is actually a bug, see https://crbug.com/354518. It looks like
// Chrome is planning to enable the fix for [1] before addressing this
// bug, so we are safe.
// [3] ISO 14496-12:2015 8.6.6.1
// It is recommended that such an edit be used to establish a presentation
// time of 0 for the first presented sample, when composition offsets are
// used.
// [4] ISO 23009-19:2018 7.5.13
// In two cases, an EditBox containing a single EditListBox with the
// following constraints may be present in the CMAF header of a CMAF track
// to adjust the presentation time of all media samples in the CMAF track.
// a) The first case is a video CMAF track file using v0 TrackRunBoxes
// with positive composition offsets to reorder video media samples.
// b) The second case is an audio CMAF track where each media sample's
// presentation time does not equal its composition time.
const int64_t pts_dts_offset = pts - dts;
if (pts_dts_offset > 0) {
if (pts < 0) {
LOG(ERROR) << "Negative presentation timestamp (" << pts
<< ") is not supported when there is an offset between "
"presentation timestamp and decoding timestamp ("
<< dts << ").";
return Status(error::MUXER_FAILURE,
"Unsupported negative pts when there is an offset between "
"pts and dts.");
}
edit_list_offset_ = pts_dts_offset;
return Status::OK;
}
if (pts_dts_offset < 0) {
LOG(ERROR) << "presentation timestamp (" << pts
<< ") is not supposed to be greater than decoding timestamp ("
<< dts << ").";
return Status(error::MUXER_FAILURE, "Not expecting pts < dts.");
}
edit_list_offset_ = std::max(-sample.pts(), static_cast<int64_t>(0));
return Status::OK;
}
void MP4Muxer::InitializeTrak(const StreamInfo* info, Track* trak) {
int64_t now = IsoTimeNow();
trak->header.creation_time = now;
trak->header.modification_time = now;
trak->header.duration = 0;
trak->media.header.creation_time = now;
trak->media.header.modification_time = now;
trak->media.header.timescale = info->time_scale();
trak->media.header.duration = 0;
if (!info->language().empty()) {
// Strip off the subtag, if any.
std::string main_language = info->language();
size_t dash = main_language.find('-');
if (dash != std::string::npos) {
main_language.erase(dash);
}
// ISO-639-2/T main language code should be 3 characters.
if (main_language.size() != 3) {
LOG(WARNING) << "'" << main_language << "' is not a valid ISO-639-2 "
<< "language code, ignoring.";
} else {
trak->media.header.language.code = main_language;
}
}
}
bool MP4Muxer::GenerateVideoTrak(const VideoStreamInfo* video_info,
Track* trak) {
InitializeTrak(video_info, trak);
// width and height specify the track's visual presentation size as
// fixed-point 16.16 values.
uint32_t pixel_width = video_info->pixel_width();
uint32_t pixel_height = video_info->pixel_height();
if (pixel_width == 0 || pixel_height == 0) {
LOG(WARNING) << "pixel width/height are not set. Assuming 1:1.";
pixel_width = 1;
pixel_height = 1;
}
const double sample_aspect_ratio =
static_cast<double>(pixel_width) / pixel_height;
trak->header.width = video_info->width() * sample_aspect_ratio * 0x10000;
trak->header.height = video_info->height() * 0x10000;
VideoSampleEntry video;
video.format =
CodecToFourCC(video_info->codec(), video_info->h26x_stream_format());
video.width = video_info->width();
video.height = video_info->height();
video.colr.raw_box = video_info->colr_data();
video.codec_configuration.data = video_info->codec_config();
if (!video.ParseExtraCodecConfigsVector(video_info->extra_config())) {
LOG(ERROR) << "Malformed extra codec configs: "
<< absl::BytesToHexString(
absl::string_view(reinterpret_cast<const char*>(
video_info->extra_config().data()),
video_info->extra_config().size()));
return false;
}
if (pixel_width != 1 || pixel_height != 1) {
video.pixel_aspect.h_spacing = pixel_width;
video.pixel_aspect.v_spacing = pixel_height;
}
SampleDescription& sample_description =
trak->media.information.sample_table.description;
sample_description.type = kVideo;
sample_description.video_entries.push_back(video);
if (video_info->is_encrypted()) {
if (video_info->has_clear_lead()) {
// Add a second entry for clear content.
sample_description.video_entries.push_back(video);
}
// Convert the first entry to an encrypted entry.
VideoSampleEntry& entry = sample_description.video_entries[0];
GenerateSinf(entry.format, video_info->encryption_config(), &entry.sinf);
entry.format = FOURCC_encv;
}
return true;
}
bool MP4Muxer::GenerateAudioTrak(const AudioStreamInfo* audio_info,
Track* trak) {
InitializeTrak(audio_info, trak);
trak->header.volume = 0x100;
AudioSampleEntry audio;
audio.format =
CodecToFourCC(audio_info->codec(), H26xStreamFormat::kUnSpecified);
switch(audio_info->codec()){
case kCodecAAC: {
DecoderConfigDescriptor* decoder_config =
audio.esds.es_descriptor.mutable_decoder_config_descriptor();
decoder_config->set_object_type(ObjectType::kISO_14496_3); // MPEG4 AAC.
decoder_config->set_max_bitrate(audio_info->max_bitrate());
decoder_config->set_avg_bitrate(audio_info->avg_bitrate());
decoder_config->mutable_decoder_specific_info_descriptor()->set_data(
audio_info->codec_config());
break;
}
case kCodecDTSC:
case kCodecDTSH:
case kCodecDTSL:
case kCodecDTSE:
case kCodecDTSM:
audio.ddts.extra_data = audio_info->codec_config();
audio.ddts.max_bitrate = audio_info->max_bitrate();
audio.ddts.avg_bitrate = audio_info->avg_bitrate();
audio.ddts.sampling_frequency = audio_info->sampling_frequency();
audio.ddts.pcm_sample_depth = audio_info->sample_bits();
break;
case kCodecDTSX:
audio.udts.data = audio_info->codec_config();
break;
case kCodecAC3:
audio.dac3.data = audio_info->codec_config();
break;
case kCodecEAC3:
audio.dec3.data = audio_info->codec_config();
break;
case kCodecAC4:
audio.dac4.data = audio_info->codec_config();
break;
case kCodecALAC:
audio.alac.data = audio_info->codec_config();
break;
case kCodecFlac:
audio.dfla.data = audio_info->codec_config();
break;
case kCodecMP3: {
DecoderConfigDescriptor* decoder_config =
audio.esds.es_descriptor.mutable_decoder_config_descriptor();
uint32_t samplerate = audio_info->sampling_frequency();
if (samplerate < 32000)
decoder_config->set_object_type(ObjectType::kISO_13818_3_MPEG1);
else
decoder_config->set_object_type(ObjectType::kISO_11172_3_MPEG1);
decoder_config->set_max_bitrate(audio_info->max_bitrate());
decoder_config->set_avg_bitrate(audio_info->avg_bitrate());
// For values of DecoderConfigDescriptor.objectTypeIndication
// that refer to streams complying with ISO/IEC 11172-3 or
// ISO/IEC 13818-3 the decoder specific information is empty
// since all necessary data is contained in the bitstream frames
// itself.
break;
}
case kCodecOpus:
audio.dops.opus_identification_header = audio_info->codec_config();
break;
case kCodecIAMF:
audio.iacb.data = audio_info->codec_config();
break;
case kCodecMha1:
case kCodecMhm1:
audio.mhac.data = audio_info->codec_config();
break;
default:
NOTIMPLEMENTED() << " Unsupported audio codec " << audio_info->codec();
return false;
}
if (audio_info->codec() == kCodecAC3 || audio_info->codec() == kCodecEAC3) {
// AC3 and EC3 does not fill in actual channel count and sample size in
// sample description entry. Instead, two constants are used.
audio.channelcount = 2;
audio.samplesize = 16;
} else if (audio_info->codec() == kCodecAC4) {
//ETSI TS 103 190-2, E.4.5 channelcount should be set to the total number of
//audio outputchannels of the default audio presentation of that track
audio.channelcount = audio_info->num_channels();
//ETSI TS 103 190-2, E.4.6 samplesize shall be set to 16.
audio.samplesize = 16;
} else if (audio_info->codec() == kCodecIAMF) {
// IAMF sets channelcount to 0
// https://aomediacodec.github.io/iamf/#iasampleentry-section
audio.channelcount = 0;
} else {
audio.channelcount = audio_info->num_channels();
audio.samplesize = audio_info->sample_bits();
}
// IAMF sets samplerate to 0
// https://aomediacodec.github.io/iamf/#iasampleentry-section
audio.samplerate =
audio_info->codec() == kCodecIAMF ? 0 : audio_info->sampling_frequency();
SampleTable& sample_table = trak->media.information.sample_table;
SampleDescription& sample_description = sample_table.description;
sample_description.type = kAudio;
sample_description.audio_entries.push_back(audio);
if (audio_info->is_encrypted()) {
if (audio_info->has_clear_lead()) {
// Add a second entry for clear content.
sample_description.audio_entries.push_back(audio);
}
// Convert the first entry to an encrypted entry.
AudioSampleEntry& entry = sample_description.audio_entries[0];
GenerateSinf(entry.format, audio_info->encryption_config(), &entry.sinf);
entry.format = FOURCC_enca;
}
if (audio_info->seek_preroll_ns() > 0) {
sample_table.sample_group_descriptions.resize(1);
SampleGroupDescription& sample_group_description =
sample_table.sample_group_descriptions.back();
sample_group_description.grouping_type = FOURCC_roll;
sample_group_description.audio_roll_recovery_entries.resize(1);
sample_group_description.audio_roll_recovery_entries[0].roll_distance =
GetRollDistance(audio_info->seek_preroll_ns(), audio.samplerate);
// sample to group box is not allowed in the init segment per CMAF
// specification. It is put in the fragment instead.
}
return true;
}
bool MP4Muxer::GenerateTextTrak(const TextStreamInfo* text_info,
Track* trak) {
InitializeTrak(text_info, trak);
if (text_info->codec_string() == "wvtt") {
// Handle WebVTT.
TextSampleEntry webvtt;
webvtt.format = FOURCC_wvtt;
// 14496-30:2014 7.5 Web Video Text Tracks Sample entry format.
// In the sample entry, a WebVTT configuration box must occur, carrying
// exactly the lines of the WebVTT file header, i.e. all text lines up to
// but excluding the 'two or more line terminators' that end the header.
webvtt.config.config = "WEBVTT";
// The spec does not define a way to carry STYLE and REGION information in
// the mp4 container.
if (!text_info->regions().empty() || !text_info->css_styles().empty()) {
LOG(INFO) << "Skipping possible style / region configuration as the spec "
"does not define a way to carry them inside ISO-BMFF files.";
}
// TODO(rkuroiwa): This should be the source file URI(s). Putting bogus
// string for now so that the box will be there for samples with overlapping
// cues.
webvtt.label.source_label = "source_label";
SampleDescription& sample_description =
trak->media.information.sample_table.description;
sample_description.type = kText;
sample_description.text_entries.push_back(webvtt);
return true;
} else if (text_info->codec_string() == "ttml") {
// Handle TTML.
TextSampleEntry ttml;
ttml.format = FOURCC_stpp;
ttml.namespace_ = ttml::TtmlGenerator::kTtNamespace;
SampleDescription& sample_description =
trak->media.information.sample_table.description;
sample_description.type = kSubtitle;
sample_description.text_entries.push_back(ttml);
return true;
}
NOTIMPLEMENTED() << text_info->codec_string()
<< " handling not implemented yet.";
return false;
}
std::optional<Range> MP4Muxer::GetInitRangeStartAndEnd() {
size_t range_offset = 0;
size_t range_size = 0;
const bool has_range = segmenter_->GetInitRange(&range_offset, &range_size);
if (!has_range)
return std::nullopt;
Range range;
SetStartAndEndFromOffsetAndSize(range_offset, range_size, &range);
return range;
}
std::optional<Range> MP4Muxer::GetIndexRangeStartAndEnd() {
size_t range_offset = 0;
size_t range_size = 0;
const bool has_range = segmenter_->GetIndexRange(&range_offset, &range_size);
if (!has_range)
return std::nullopt;
Range range;
SetStartAndEndFromOffsetAndSize(range_offset, range_size, &range);
return range;
}
void MP4Muxer::FireOnMediaStartEvent() {
if (!muxer_listener())
return;
if (streams().size() > 1) {
LOG(ERROR) << "MuxerListener cannot take more than 1 stream.";
return;
}
DCHECK(!streams().empty()) << "Media started without a stream.";
const int32_t timescale = segmenter_->GetReferenceTimeScale();
muxer_listener()->OnMediaStart(options(), *streams().front(), timescale,
MuxerListener::kContainerMp4);
}
void MP4Muxer::FireOnMediaEndEvent() {
if (!muxer_listener())
return;
MuxerListener::MediaRanges media_range;
media_range.init_range = GetInitRangeStartAndEnd();
media_range.index_range = GetIndexRangeStartAndEnd();
media_range.subsegment_ranges = segmenter_->GetSegmentRanges();
const float duration_seconds = static_cast<float>(segmenter_->GetDuration());
muxer_listener()->OnMediaEnd(media_range, duration_seconds);
}
uint64_t MP4Muxer::IsoTimeNow() {
// Time in seconds from Jan. 1, 1904 to epoch time, i.e. Jan. 1, 1970.
const uint64_t kIsomTimeOffset = 2082844800l;
// Get the current system time since January 1, 1970, in seconds.
std::int64_t secondsSince1970 = Now();
// Add the offset of seconds between January 1, 1970, and January 1, 1904.
return secondsSince1970 + kIsomTimeOffset;
}
} // namespace mp4
} // namespace media
} // namespace shaka
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