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shaka-packager/packager/mpd/base/mpd_builder.cc

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// Copyright 2014 Google Inc. 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/mpd/base/mpd_builder.h"
#include <libxml/tree.h>
#include <libxml/xmlstring.h>
#include <cmath>
#include <list>
#include <string>
#include "packager/base/files/file_path.h"
#include "packager/base/logging.h"
#include "packager/base/memory/scoped_ptr.h"
#include "packager/base/strings/string_number_conversions.h"
#include "packager/base/strings/stringprintf.h"
#include "packager/base/synchronization/lock.h"
#include "packager/base/time/time.h"
#include "packager/media/file/file.h"
#include "packager/mpd/base/content_protection_element.h"
#include "packager/mpd/base/language_utils.h"
#include "packager/mpd/base/mpd_utils.h"
#include "packager/mpd/base/xml/xml_node.h"
namespace edash_packager {
using base::FilePath;
using xml::XmlNode;
using xml::RepresentationXmlNode;
using xml::AdaptationSetXmlNode;
namespace {
const int kAdaptationSetGroupNotSet = -1;
std::string GetMimeType(const std::string& prefix,
MediaInfo::ContainerType container_type) {
switch (container_type) {
case MediaInfo::CONTAINER_MP4:
return prefix + "/mp4";
case MediaInfo::CONTAINER_MPEG2_TS:
// NOTE: DASH MPD spec uses lowercase but RFC3555 says uppercase.
return prefix + "/MP2T";
case MediaInfo::CONTAINER_WEBM:
return prefix + "/webm";
default:
break;
}
// Unsupported container types should be rejected/handled by the caller.
NOTREACHED() << "Unrecognized container type: " << container_type;
return std::string();
}
void AddMpdNameSpaceInfo(XmlNode* mpd) {
DCHECK(mpd);
static const char kXmlNamespace[] = "urn:mpeg:DASH:schema:MPD:2011";
static const char kXmlNamespaceXsi[] =
"http://www.w3.org/2001/XMLSchema-instance";
static const char kXmlNamespaceXlink[] = "http://www.w3.org/1999/xlink";
static const char kDashSchemaMpd2011[] =
"urn:mpeg:DASH:schema:MPD:2011 DASH-MPD.xsd";
static const char kCencNamespace[] = "urn:mpeg:cenc:2013";
mpd->SetStringAttribute("xmlns", kXmlNamespace);
mpd->SetStringAttribute("xmlns:xsi", kXmlNamespaceXsi);
mpd->SetStringAttribute("xmlns:xlink", kXmlNamespaceXlink);
mpd->SetStringAttribute("xsi:schemaLocation", kDashSchemaMpd2011);
mpd->SetStringAttribute("xmlns:cenc", kCencNamespace);
}
bool IsPeriodNode(xmlNodePtr node) {
DCHECK(node);
int kEqual = 0;
return xmlStrcmp(node->name, reinterpret_cast<const xmlChar*>("Period")) ==
kEqual;
}
// Find the first <Period> element. This does not recurse down the tree,
// only checks direct children. Returns the pointer to Period element on
// success, otherwise returns false.
// As noted here, we must traverse.
// http://www.xmlsoft.org/tutorial/ar01s04.html
xmlNodePtr FindPeriodNode(XmlNode* xml_node) {
for (xmlNodePtr node = xml_node->GetRawPtr()->xmlChildrenNode; node != NULL;
node = node->next) {
if (IsPeriodNode(node))
return node;
}
return NULL;
}
bool Positive(double d) {
return d > 0.0;
}
// Return current time in XML DateTime format.
std::string XmlDateTimeNowWithOffset(int32_t offset_seconds) {
base::Time time = base::Time::Now();
time += base::TimeDelta::FromSeconds(offset_seconds);
base::Time::Exploded time_exploded;
time.UTCExplode(&time_exploded);
return base::StringPrintf("%4d-%02d-%02dT%02d:%02d:%02d", time_exploded.year,
time_exploded.month, time_exploded.day_of_month,
time_exploded.hour, time_exploded.minute,
time_exploded.second);
}
void SetIfPositive(const char* attr_name, double value, XmlNode* mpd) {
if (Positive(value)) {
mpd->SetStringAttribute(attr_name, SecondsToXmlDuration(value));
}
}
uint32_t GetTimeScale(const MediaInfo& media_info) {
if (media_info.has_reference_time_scale()) {
return media_info.reference_time_scale();
}
if (media_info.has_video_info()) {
return media_info.video_info().time_scale();
}
if (media_info.has_audio_info()) {
return media_info.audio_info().time_scale();
}
LOG(WARNING) << "No timescale specified, using 1 as timescale.";
return 1;
}
uint64_t LastSegmentStartTime(const SegmentInfo& segment_info) {
return segment_info.start_time + segment_info.duration * segment_info.repeat;
}
// This is equal to |segment_info| end time
uint64_t LastSegmentEndTime(const SegmentInfo& segment_info) {
return segment_info.start_time +
segment_info.duration * (segment_info.repeat + 1);
}
uint64_t LatestSegmentStartTime(const std::list<SegmentInfo>& segments) {
DCHECK(!segments.empty());
const SegmentInfo& latest_segment = segments.back();
return LastSegmentStartTime(latest_segment);
}
// Given |timeshift_limit|, finds out the number of segments that are no longer
// valid and should be removed from |segment_info|.
int SearchTimedOutRepeatIndex(uint64_t timeshift_limit,
const SegmentInfo& segment_info) {
DCHECK_LE(timeshift_limit, LastSegmentEndTime(segment_info));
if (timeshift_limit < segment_info.start_time)
return 0;
return (timeshift_limit - segment_info.start_time) / segment_info.duration;
}
// Overload this function to support different types of |output|.
// Note that this could be done by call MpdBuilder::ToString() and use the
// result to write to a file, it requires an extra copy.
bool WriteXmlCharArrayToOutput(xmlChar* doc,
int doc_size,
std::string* output) {
DCHECK(doc);
DCHECK(output);
output->assign(doc, doc + doc_size);
return true;
}
bool WriteXmlCharArrayToOutput(xmlChar* doc,
int doc_size,
media::File* output) {
DCHECK(doc);
DCHECK(output);
if (output->Write(doc, doc_size) < doc_size)
return false;
return output->Flush();
}
std::string MakePathRelative(const std::string& path,
const std::string& mpd_dir) {
return (path.find(mpd_dir) == 0) ? path.substr(mpd_dir.size()) : path;
}
// Check whether the video info has width and height.
// DASH IOP also requires several other fields for video representations, namely
// width, height, framerate, and sar.
bool HasRequiredVideoFields(const MediaInfo_VideoInfo& video_info) {
if (!video_info.has_height() || !video_info.has_width()) {
LOG(ERROR)
<< "Width and height are required fields for generating a valid MPD.";
return false;
}
// These fields are not required for a valid MPD, but required for DASH IOP
// compliant MPD. MpdBuilder can keep generating MPDs without these fields.
LOG_IF(WARNING, !video_info.has_time_scale())
<< "Video info does not contain timescale required for "
"calculating framerate. @frameRate is required for DASH IOP.";
LOG_IF(WARNING, !video_info.has_frame_duration())
<< "Video info does not contain frame duration required "
"for calculating framerate. @frameRate is required for DASH IOP.";
LOG_IF(WARNING, !video_info.has_pixel_width())
<< "Video info does not contain pixel_width to calculate the sample "
"aspect ratio required for DASH IOP.";
LOG_IF(WARNING, !video_info.has_pixel_height())
<< "Video info does not contain pixel_height to calculate the sample "
"aspect ratio required for DASH IOP.";
return true;
}
// Euclidean algorithm.
// gcd(a,0) = a
// gcd(a,b) = gcd(b, a % b)
uint32_t GreatestCommonDivisor(uint32_t a, uint32_t b) {
while (b != 0) {
const uint32_t new_b = a % b;
a = b;
b = new_b;
}
return a;
}
// Returns the picture aspect ratio string e.g. "16:9", "4:3".
std::string GetPictureAspectRatio(uint32_t width, uint32_t height,
uint32_t pixel_width, uint32_t pixel_height) {
const uint32_t scaled_width = pixel_width * width;
const uint32_t scaled_height = pixel_height * height;
const uint32_t gcd = GreatestCommonDivisor(scaled_width, scaled_height);
DCHECK_NE(gcd, 0u) << "GCD of width*pix_width (" << scaled_width
<< ") and height*pix_height (" << scaled_height
<< ") is 0.";
const uint32_t par_x = scaled_width / gcd;
const uint32_t par_y = scaled_height / gcd;
return base::IntToString(par_x) + ":" + base::IntToString(par_y);
}
// Adds an entry to picture_aspect_ratio if the size of picture_aspect_ratio is
// less than 2 and video_info has both pixel width and pixel height.
void AddPictureAspectRatio(
const MediaInfo::VideoInfo& video_info,
std::set<std::string>* picture_aspect_ratio) {
// If there are more than one entries in picture_aspect_ratio, the @par
// attribute cannot be set, so skip.
if (picture_aspect_ratio->size() > 1)
return;
if (video_info.width() == 0 || video_info.height() == 0 ||
video_info.pixel_width() == 0 || video_info.pixel_height() == 0) {
// If there is even one Representation without a @sar attribute, @par cannot
// be calculated.
// Just populate the set with at least 2 bogus strings so that further call
// to this function will bail out immediately.
picture_aspect_ratio->insert("bogus");
picture_aspect_ratio->insert("entries");
return;
}
const std::string par = GetPictureAspectRatio(
video_info.width(), video_info.height(),
video_info.pixel_width(), video_info.pixel_height());
DVLOG(1) << "Setting par as: " << par
<< " for video with width: " << video_info.width()
<< " height: " << video_info.height()
<< " pixel_width: " << video_info.pixel_width() << " pixel_height; "
<< video_info.pixel_height();
picture_aspect_ratio->insert(par);
}
std::string RoleToText(AdaptationSet::Role role) {
// Using switch so that the compiler can detect whether there is a case that's
// not being handled.
switch (role) {
case AdaptationSet::kRoleCaption:
return "caption";
case AdaptationSet::kRoleSubtitle:
return "subtitle";
case AdaptationSet::kRoleMain:
return "main";
case AdaptationSet::kRoleAlternate:
return "alternate";
case AdaptationSet::kRoleSupplementary:
return "supplementary";
case AdaptationSet::kRoleCommentary:
return "commentary";
case AdaptationSet::kRoleDub:
return "dub";
default:
NOTREACHED();
return "";
}
NOTREACHED();
return "";
}
// Spooky static initialization/cleanup of libxml.
class LibXmlInitializer {
public:
LibXmlInitializer() : initialized_(false) {
base::AutoLock lock(lock_);
if (!initialized_) {
xmlInitParser();
initialized_ = true;
}
}
~LibXmlInitializer() {
base::AutoLock lock(lock_);
if (initialized_) {
xmlCleanupParser();
initialized_ = false;
}
}
private:
base::Lock lock_;
bool initialized_;
DISALLOW_COPY_AND_ASSIGN(LibXmlInitializer);
};
} // namespace
MpdBuilder::MpdBuilder(MpdType type, const MpdOptions& mpd_options)
: type_(type),
mpd_options_(mpd_options),
adaptation_sets_deleter_(&adaptation_sets_) {
}
MpdBuilder::~MpdBuilder() {
}
void MpdBuilder::AddBaseUrl(const std::string& base_url) {
base::AutoLock scoped_lock(lock_);
base_urls_.push_back(base_url);
}
AdaptationSet* MpdBuilder::AddAdaptationSet(const std::string& lang) {
base::AutoLock scoped_lock(lock_);
scoped_ptr<AdaptationSet> adaptation_set(
new AdaptationSet(adaptation_set_counter_.GetNext(), lang, mpd_options_,
&representation_counter_));
DCHECK(adaptation_set);
adaptation_sets_.push_back(adaptation_set.get());
return adaptation_set.release();
}
bool MpdBuilder::WriteMpdToFile(media::File* output_file) {
base::AutoLock scoped_lock(lock_);
DCHECK(output_file);
return WriteMpdToOutput(output_file);
}
bool MpdBuilder::ToString(std::string* output) {
base::AutoLock scoped_lock(lock_);
DCHECK(output);
return WriteMpdToOutput(output);
}
template <typename OutputType>
bool MpdBuilder::WriteMpdToOutput(OutputType* output) {
static LibXmlInitializer lib_xml_initializer;
xml::ScopedXmlPtr<xmlDoc>::type doc(GenerateMpd());
if (!doc.get())
return false;
static const int kNiceFormat = 1;
int doc_str_size = 0;
xmlChar* doc_str = NULL;
xmlDocDumpFormatMemoryEnc(doc.get(), &doc_str, &doc_str_size, "UTF-8",
kNiceFormat);
bool result = WriteXmlCharArrayToOutput(doc_str, doc_str_size, output);
xmlFree(doc_str);
// Cleanup, free the doc.
doc.reset();
return result;
}
xmlDocPtr MpdBuilder::GenerateMpd() {
// Setup nodes.
static const char kXmlVersion[] = "1.0";
xml::ScopedXmlPtr<xmlDoc>::type doc(xmlNewDoc(BAD_CAST kXmlVersion));
XmlNode mpd("MPD");
// Iterate thru AdaptationSets and add them to one big Period element.
XmlNode period("Period");
std::list<AdaptationSet*>::iterator adaptation_sets_it =
adaptation_sets_.begin();
for (; adaptation_sets_it != adaptation_sets_.end(); ++adaptation_sets_it) {
xml::ScopedXmlPtr<xmlNode>::type child((*adaptation_sets_it)->GetXml());
if (!child.get() || !period.AddChild(child.Pass()))
return NULL;
}
// Add baseurls to MPD.
std::list<std::string>::const_iterator base_urls_it = base_urls_.begin();
for (; base_urls_it != base_urls_.end(); ++base_urls_it) {
XmlNode base_url("BaseURL");
base_url.SetContent(*base_urls_it);
if (!mpd.AddChild(base_url.PassScopedPtr()))
return NULL;
}
if (type_ == kDynamic) {
// This is the only Period and it is a regular period.
period.SetStringAttribute("start", "PT0S");
}
if (!mpd.AddChild(period.PassScopedPtr()))
return NULL;
AddMpdNameSpaceInfo(&mpd);
AddCommonMpdInfo(&mpd);
switch (type_) {
case kStatic:
AddStaticMpdInfo(&mpd);
break;
case kDynamic:
AddDynamicMpdInfo(&mpd);
break;
default:
NOTREACHED() << "Unknown MPD type: " << type_;
break;
}
DCHECK(doc);
xmlDocSetRootElement(doc.get(), mpd.Release());
return doc.release();
}
void MpdBuilder::AddCommonMpdInfo(XmlNode* mpd_node) {
if (Positive(mpd_options_.min_buffer_time)) {
mpd_node->SetStringAttribute(
"minBufferTime", SecondsToXmlDuration(mpd_options_.min_buffer_time));
} else {
LOG(ERROR) << "minBufferTime value not specified.";
// TODO(tinskip): Propagate error.
}
}
void MpdBuilder::AddStaticMpdInfo(XmlNode* mpd_node) {
DCHECK(mpd_node);
DCHECK_EQ(MpdBuilder::kStatic, type_);
static const char kStaticMpdType[] = "static";
static const char kStaticMpdProfile[] =
"urn:mpeg:dash:profile:isoff-on-demand:2011";
mpd_node->SetStringAttribute("type", kStaticMpdType);
mpd_node->SetStringAttribute("profiles", kStaticMpdProfile);
mpd_node->SetStringAttribute(
"mediaPresentationDuration",
SecondsToXmlDuration(GetStaticMpdDuration(mpd_node)));
}
void MpdBuilder::AddDynamicMpdInfo(XmlNode* mpd_node) {
DCHECK(mpd_node);
DCHECK_EQ(MpdBuilder::kDynamic, type_);
static const char kDynamicMpdType[] = "dynamic";
static const char kDynamicMpdProfile[] =
"urn:mpeg:dash:profile:isoff-live:2011";
mpd_node->SetStringAttribute("type", kDynamicMpdType);
mpd_node->SetStringAttribute("profiles", kDynamicMpdProfile);
// 'availabilityStartTime' is required for dynamic profile. Calculate if
// not already calculated.
if (availability_start_time_.empty()) {
double earliest_presentation_time;
if (GetEarliestTimestamp(&earliest_presentation_time)) {
availability_start_time_ =
XmlDateTimeNowWithOffset(mpd_options_.availability_time_offset -
std::ceil(earliest_presentation_time));
} else {
LOG(ERROR) << "Could not determine the earliest segment presentation "
"time for availabilityStartTime calculation.";
// TODO(tinskip). Propagate an error.
}
}
if (!availability_start_time_.empty())
mpd_node->SetStringAttribute("availabilityStartTime",
availability_start_time_);
if (Positive(mpd_options_.minimum_update_period)) {
mpd_node->SetStringAttribute(
"minimumUpdatePeriod",
SecondsToXmlDuration(mpd_options_.minimum_update_period));
} else {
LOG(WARNING) << "The profile is dynamic but no minimumUpdatePeriod "
"specified.";
}
SetIfPositive("timeShiftBufferDepth", mpd_options_.time_shift_buffer_depth,
mpd_node);
SetIfPositive("suggestedPresentationDelay",
mpd_options_.suggested_presentation_delay, mpd_node);
}
float MpdBuilder::GetStaticMpdDuration(XmlNode* mpd_node) {
DCHECK(mpd_node);
DCHECK_EQ(MpdBuilder::kStatic, type_);
xmlNodePtr period_node = FindPeriodNode(mpd_node);
DCHECK(period_node) << "Period element must be a child of mpd_node.";
DCHECK(IsPeriodNode(period_node));
// Attribute mediaPresentationDuration must be present for 'static' MPD. So
// setting "PT0S" is required even if none of the representaions have duration
// attribute.
float max_duration = 0.0f;
for (xmlNodePtr adaptation_set = xmlFirstElementChild(period_node);
adaptation_set; adaptation_set = xmlNextElementSibling(adaptation_set)) {
for (xmlNodePtr representation = xmlFirstElementChild(adaptation_set);
representation;
representation = xmlNextElementSibling(representation)) {
float duration = 0.0f;
if (GetDurationAttribute(representation, &duration)) {
max_duration = max_duration > duration ? max_duration : duration;
// 'duration' attribute is there only to help generate MPD, not
// necessary for MPD, remove the attribute.
xmlUnsetProp(representation, BAD_CAST "duration");
}
}
}
return max_duration;
}
bool MpdBuilder::GetEarliestTimestamp(double* timestamp_seconds) {
DCHECK(timestamp_seconds);
double earliest_timestamp(-1);
for (std::list<AdaptationSet*>::const_iterator iter =
adaptation_sets_.begin();
iter != adaptation_sets_.end(); ++iter) {
double timestamp;
if ((*iter)->GetEarliestTimestamp(&timestamp) &&
((earliest_timestamp < 0) || (timestamp < earliest_timestamp))) {
earliest_timestamp = timestamp;
}
}
if (earliest_timestamp < 0)
return false;
*timestamp_seconds = earliest_timestamp;
return true;
}
void MpdBuilder::MakePathsRelativeToMpd(const std::string& mpd_path,
MediaInfo* media_info) {
DCHECK(media_info);
const std::string kFileProtocol("file://");
std::string mpd_file_path = (mpd_path.find(kFileProtocol) == 0)
? mpd_path.substr(kFileProtocol.size())
: mpd_path;
if (!mpd_file_path.empty()) {
std::string mpd_dir(
FilePath(mpd_file_path).DirName().AsEndingWithSeparator().value());
if (!mpd_dir.empty()) {
if (media_info->has_media_file_name()) {
media_info->set_media_file_name(
MakePathRelative(media_info->media_file_name(), mpd_dir));
}
if (media_info->has_init_segment_name()) {
media_info->set_init_segment_name(
MakePathRelative(media_info->init_segment_name(), mpd_dir));
}
if (media_info->has_segment_template()) {
media_info->set_segment_template(
MakePathRelative(media_info->segment_template(), mpd_dir));
}
}
}
}
AdaptationSet::AdaptationSet(uint32_t adaptation_set_id,
const std::string& lang,
const MpdOptions& mpd_options,
base::AtomicSequenceNumber* counter)
: representations_deleter_(&representations_),
representation_counter_(counter),
id_(adaptation_set_id),
lang_(lang),
mpd_options_(mpd_options),
group_(kAdaptationSetGroupNotSet) {
DCHECK(counter);
}
AdaptationSet::~AdaptationSet() {
}
Representation* AdaptationSet::AddRepresentation(const MediaInfo& media_info) {
base::AutoLock scoped_lock(lock_);
scoped_ptr<Representation> representation(new Representation(
media_info, mpd_options_, representation_counter_->GetNext()));
if (!representation->Init())
return NULL;
// For videos, record the width, height, and the frame rate to calculate the
// max {width,height,framerate} required for DASH IOP.
if(media_info.has_video_info()) {
const MediaInfo::VideoInfo& video_info = media_info.video_info();
DCHECK(video_info.has_width());
DCHECK(video_info.has_height());
video_widths_.insert(video_info.width());
video_heights_.insert(video_info.height());
if (video_info.has_time_scale() && video_info.has_frame_duration()) {
video_frame_rates_[static_cast<double>(video_info.time_scale()) /
video_info.frame_duration()] =
base::IntToString(video_info.time_scale()) + "/" +
base::IntToString(video_info.frame_duration());
}
AddPictureAspectRatio(video_info, &picture_aspect_ratio_);
}
if (media_info.has_video_info()) {
content_type_ = "video";
} else if (media_info.has_audio_info()) {
content_type_ = "audio";
}
representations_.push_back(representation.get());
return representation.release();
}
void AdaptationSet::AddContentProtectionElement(
const ContentProtectionElement& content_protection_element) {
base::AutoLock scoped_lock(lock_);
content_protection_elements_.push_back(content_protection_element);
RemoveDuplicateAttributes(&content_protection_elements_.back());
}
void AdaptationSet::AddRole(Role role) {
roles_.insert(role);
}
// Creates a copy of <AdaptationSet> xml element, iterate thru all the
// <Representation> (child) elements and add them to the copy.
xml::ScopedXmlPtr<xmlNode>::type AdaptationSet::GetXml() {
base::AutoLock scoped_lock(lock_);
AdaptationSetXmlNode adaptation_set;
if (!adaptation_set.AddContentProtectionElements(
content_protection_elements_)) {
return xml::ScopedXmlPtr<xmlNode>::type();
}
std::list<Representation*>::iterator representation_it =
representations_.begin();
for (; representation_it != representations_.end(); ++representation_it) {
xml::ScopedXmlPtr<xmlNode>::type child((*representation_it)->GetXml());
if (!child || !adaptation_set.AddChild(child.Pass()))
return xml::ScopedXmlPtr<xmlNode>::type();
}
adaptation_set.SetId(id_);
adaptation_set.SetStringAttribute("contentType", content_type_);
if (!lang_.empty() && lang_ != "und") {
adaptation_set.SetStringAttribute("lang", LanguageToShortestForm(lang_));
}
// Note that std::{set,map} are ordered, so the last element is the max value.
if (video_widths_.size() == 1) {
adaptation_set.SetIntegerAttribute("width", *video_widths_.begin());
} else if (video_widths_.size() > 1) {
adaptation_set.SetIntegerAttribute("maxWidth", *video_widths_.rbegin());
}
if (video_heights_.size() == 1) {
adaptation_set.SetIntegerAttribute("height", *video_heights_.begin());
} else if (video_heights_.size() > 1) {
adaptation_set.SetIntegerAttribute("maxHeight", *video_heights_.rbegin());
}
if (video_frame_rates_.size() == 1) {
adaptation_set.SetStringAttribute("frameRate",
video_frame_rates_.begin()->second);
} else if (video_frame_rates_.size() > 1) {
adaptation_set.SetStringAttribute("maxFrameRate",
video_frame_rates_.rbegin()->second);
}
if (picture_aspect_ratio_.size() == 1)
adaptation_set.SetStringAttribute("par", *picture_aspect_ratio_.begin());
if (group_ >= 0)
adaptation_set.SetIntegerAttribute("group", group_);
for (std::set<Role>::const_iterator role_it = roles_.begin();
role_it != roles_.end(); ++role_it) {
adaptation_set.AddRoleElement("urn:mpeg:dash:role:2011",
RoleToText(*role_it));
}
return adaptation_set.PassScopedPtr();
}
bool AdaptationSet::GetEarliestTimestamp(double* timestamp_seconds) {
DCHECK(timestamp_seconds);
base::AutoLock scoped_lock(lock_);
double earliest_timestamp(-1);
for (std::list<Representation*>::const_iterator iter =
representations_.begin();
iter != representations_.end(); ++iter) {
double timestamp;
if ((*iter)->GetEarliestTimestamp(&timestamp) &&
((earliest_timestamp < 0) || (timestamp < earliest_timestamp))) {
earliest_timestamp = timestamp;
}
}
if (earliest_timestamp < 0)
return false;
*timestamp_seconds = earliest_timestamp;
return true;
}
Representation::Representation(const MediaInfo& media_info,
const MpdOptions& mpd_options,
uint32_t id)
: media_info_(media_info),
id_(id),
bandwidth_estimator_(BandwidthEstimator::kUseAllBlocks),
mpd_options_(mpd_options),
start_number_(1) {
}
Representation::~Representation() {
}
bool Representation::Init() {
codecs_ = GetCodecs(media_info_);
if (codecs_.empty()) {
LOG(ERROR) << "Missing codec info in MediaInfo.";
return false;
}
const bool has_video_info = media_info_.has_video_info();
const bool has_audio_info = media_info_.has_audio_info();
if (!has_video_info && !has_audio_info) {
// This is an error. Segment information can be in AdaptationSet, Period, or
// MPD but the interface does not provide a way to set them.
// See 5.3.9.1 ISO 23009-1:2012 for segment info.
LOG(ERROR) << "Representation needs video or audio.";
return false;
}
if (media_info_.container_type() == MediaInfo::CONTAINER_UNKNOWN) {
LOG(ERROR) << "'container_type' in MediaInfo cannot be CONTAINER_UNKNOWN.";
return false;
}
// For mimetypes, this checks the video and then audio. Usually when there is
// audio + video, we take video/<type>.
if (has_video_info) {
mime_type_ = GetVideoMimeType();
if (!HasRequiredVideoFields(media_info_.video_info())) {
LOG(ERROR) << "Missing required fields to create a video Representation.";
return false;
}
} else if (has_audio_info) {
mime_type_ = GetAudioMimeType();
}
return true;
}
void Representation::AddContentProtectionElement(
const ContentProtectionElement& content_protection_element) {
base::AutoLock scoped_lock(lock_);
content_protection_elements_.push_back(content_protection_element);
RemoveDuplicateAttributes(&content_protection_elements_.back());
}
void Representation::AddNewSegment(uint64_t start_time,
uint64_t duration,
uint64_t size) {
if (start_time == 0 && duration == 0) {
LOG(WARNING) << "Got segment with start_time and duration == 0. Ignoring.";
return;
}
base::AutoLock scoped_lock(lock_);
if (IsContiguous(start_time, duration, size)) {
++segment_infos_.back().repeat;
} else {
SegmentInfo s = {start_time, duration, /* Not repeat. */ 0};
segment_infos_.push_back(s);
}
bandwidth_estimator_.AddBlock(
size, static_cast<double>(duration) / media_info_.reference_time_scale());
SlideWindow();
DCHECK_GE(segment_infos_.size(), 1u);
}
void Representation::SetSampleDuration(uint32_t sample_duration) {
// Assume single video info.
if (media_info_.has_video_info())
media_info_.mutable_video_info()->set_frame_duration(sample_duration);
}
// Uses info in |media_info_| and |content_protection_elements_| to create a
// "Representation" node.
// MPD schema has strict ordering. The following must be done in order.
// AddVideoInfo() (possibly adds FramePacking elements), AddAudioInfo() (Adds
// AudioChannelConfig elements), AddContentProtectionElements*(), and
// AddVODOnlyInfo() (Adds segment info).
xml::ScopedXmlPtr<xmlNode>::type Representation::GetXml() {
base::AutoLock scoped_lock(lock_);
if (!HasRequiredMediaInfoFields()) {
LOG(ERROR) << "MediaInfo missing required fields.";
return xml::ScopedXmlPtr<xmlNode>::type();
}
const uint64_t bandwidth = media_info_.has_bandwidth()
? media_info_.bandwidth()
: bandwidth_estimator_.Estimate();
DCHECK(!(HasVODOnlyFields(media_info_) && HasLiveOnlyFields(media_info_)));
RepresentationXmlNode representation;
// Mandatory fields for Representation.
representation.SetId(id_);
representation.SetIntegerAttribute("bandwidth", bandwidth);
representation.SetStringAttribute("codecs", codecs_);
representation.SetStringAttribute("mimeType", mime_type_);
const bool has_video_info = media_info_.has_video_info();
const bool has_audio_info = media_info_.has_audio_info();
if (has_video_info &&
!representation.AddVideoInfo(media_info_.video_info())) {
LOG(ERROR) << "Failed to add video info to Representation XML.";
return xml::ScopedXmlPtr<xmlNode>::type();
}
if (has_audio_info &&
!representation.AddAudioInfo(media_info_.audio_info())) {
LOG(ERROR) << "Failed to add audio info to Representation XML.";
return xml::ScopedXmlPtr<xmlNode>::type();
}
if (!representation.AddContentProtectionElements(
content_protection_elements_)) {
return xml::ScopedXmlPtr<xmlNode>::type();
}
if (HasVODOnlyFields(media_info_) &&
!representation.AddVODOnlyInfo(media_info_)) {
LOG(ERROR) << "Failed to add VOD segment info.";
return xml::ScopedXmlPtr<xmlNode>::type();
}
if (HasLiveOnlyFields(media_info_) &&
!representation.AddLiveOnlyInfo(media_info_, segment_infos_,
start_number_)) {
LOG(ERROR) << "Failed to add Live info.";
return xml::ScopedXmlPtr<xmlNode>::type();
}
// TODO(rkuroiwa): It is likely that all representations have the exact same
// SegmentTemplate. Optimize and propagate the tag up to AdaptationSet level.
return representation.PassScopedPtr();
}
bool Representation::HasRequiredMediaInfoFields() {
if (HasVODOnlyFields(media_info_) && HasLiveOnlyFields(media_info_)) {
LOG(ERROR) << "MediaInfo cannot have both VOD and Live fields.";
return false;
}
if (!media_info_.has_container_type()) {
LOG(ERROR) << "MediaInfo missing required field: container_type.";
return false;
}
if (HasVODOnlyFields(media_info_) && !media_info_.has_bandwidth()) {
LOG(ERROR) << "Missing 'bandwidth' field. MediaInfo requires bandwidth for "
"static profile for generating a valid MPD.";
return false;
}
VLOG_IF(3, HasLiveOnlyFields(media_info_) && !media_info_.has_bandwidth())
<< "MediaInfo missing field 'bandwidth'. Using estimated from "
"segment size.";
return true;
}
bool Representation::IsContiguous(uint64_t start_time,
uint64_t duration,
uint64_t size) const {
if (segment_infos_.empty())
return false;
// Contiguous segment.
const SegmentInfo& previous = segment_infos_.back();
const uint64_t previous_segment_end_time =
previous.start_time + previous.duration * (previous.repeat + 1);
if (previous_segment_end_time == start_time &&
segment_infos_.back().duration == duration) {
return true;
}
// No out of order segments.
const uint64_t previous_segment_start_time =
previous.start_time + previous.duration * previous.repeat;
if (previous_segment_start_time >= start_time) {
LOG(ERROR) << "Segments should not be out of order segment. Adding segment "
"with start_time == "
<< start_time << " but the previous segment starts at "
<< previous.start_time << ".";
return false;
}
// A gap since previous.
const uint64_t kRoundingErrorGrace = 5;
if (previous_segment_end_time + kRoundingErrorGrace < start_time) {
LOG(WARNING) << "Found a gap of size "
<< (start_time - previous_segment_end_time)
<< " > kRoundingErrorGrace (" << kRoundingErrorGrace
<< "). The new segment starts at " << start_time
<< " but the previous segment ends at "
<< previous_segment_end_time << ".";
return false;
}
// No overlapping segments.
if (start_time < previous_segment_end_time - kRoundingErrorGrace) {
LOG(WARNING)
<< "Segments should not be overlapping. The new segment starts at "
<< start_time << " but the previous segment ends at "
<< previous_segment_end_time << ".";
return false;
}
// Within rounding error grace but technically not contiguous in terms of MPD.
return false;
}
void Representation::SlideWindow() {
DCHECK(!segment_infos_.empty());
if (mpd_options_.time_shift_buffer_depth <= 0.0)
return;
const uint32_t time_scale = GetTimeScale(media_info_);
DCHECK_GT(time_scale, 0u);
uint64_t time_shift_buffer_depth =
static_cast<uint64_t>(mpd_options_.time_shift_buffer_depth * time_scale);
// The start time of the latest segment is considered the current_play_time,
// and this should guarantee that the latest segment will stay in the list.
const uint64_t current_play_time = LatestSegmentStartTime(segment_infos_);
if (current_play_time <= time_shift_buffer_depth)
return;
const uint64_t timeshift_limit = current_play_time - time_shift_buffer_depth;
// First remove all the SegmentInfos that are completely out of range, by
// looking at the very last segment's end time.
std::list<SegmentInfo>::iterator first = segment_infos_.begin();
std::list<SegmentInfo>::iterator last = first;
size_t num_segments_removed = 0;
for (; last != segment_infos_.end(); ++last) {
const uint64_t last_segment_end_time = LastSegmentEndTime(*last);
if (timeshift_limit < last_segment_end_time)
break;
num_segments_removed += last->repeat + 1;
}
segment_infos_.erase(first, last);
start_number_ += num_segments_removed;
// Now some segment in the first SegmentInfo should be left in the list.
SegmentInfo* first_segment_info = &segment_infos_.front();
DCHECK_LE(timeshift_limit, LastSegmentEndTime(*first_segment_info));
// Identify which segments should still be in the SegmentInfo.
const int repeat_index =
SearchTimedOutRepeatIndex(timeshift_limit, *first_segment_info);
CHECK_GE(repeat_index, 0);
if (repeat_index == 0)
return;
first_segment_info->start_time = first_segment_info->start_time +
first_segment_info->duration * repeat_index;
first_segment_info->repeat = first_segment_info->repeat - repeat_index;
start_number_ += repeat_index;
}
std::string Representation::GetVideoMimeType() const {
return GetMimeType("video", media_info_.container_type());
}
std::string Representation::GetAudioMimeType() const {
return GetMimeType("audio", media_info_.container_type());
}
bool Representation::GetEarliestTimestamp(double* timestamp_seconds) {
DCHECK(timestamp_seconds);
base::AutoLock scoped_lock(lock_);
if (segment_infos_.empty())
return false;
*timestamp_seconds = static_cast<double>(segment_infos_.begin()->start_time) /
GetTimeScale(media_info_);
return true;
}
} // namespace edash_packager
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