sample_muxer_metadata.cc - platform/external/libwebm - Git at Google

 // Copyright (c) 2012 The WebM project authors. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the LICENSE file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS.  All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 //
 // This sample application demonstrates how to use the matroska parser
 // library, which allows clients to handle a matroska format file.

 #include "sample_muxer_metadata.h"

 #include <cstdio>
 #include <string>

 #include "mkvmuxer/mkvmuxer.h"
 #include "webvtt/vttreader.h"

 SampleMuxerMetadata::SampleMuxerMetadata() : segment_(NULL) {}

 bool SampleMuxerMetadata::Init(mkvmuxer::Segment* segment) {
   if (segment == NULL || segment_ != NULL)
     return false;

   segment_ = segment;
   return true;
 }

 bool SampleMuxerMetadata::Load(const char* file, Kind kind) {
   if (kind == kChapters)
     return LoadChapters(file);

   uint64_t track_num;

   if (!AddTrack(kind, &track_num)) {
     printf("Unable to add track for WebVTT file \"%s\"\n", file);
     return false;
   }

   return Parse(file, kind, track_num);
 }

 bool SampleMuxerMetadata::AddChapters() {
   typedef cue_list_t::const_iterator iter_t;
   iter_t i = chapter_cues_.begin();
   const iter_t j = chapter_cues_.end();

   while (i != j) {
     const cue_t& chapter = *i++;

     if (!AddChapter(chapter))
       return false;
   }

   return true;
 }

 bool SampleMuxerMetadata::Write(int64_t time_ns) {
   typedef cues_set_t::iterator iter_t;

   iter_t i = cues_set_.begin();
   const iter_t j = cues_set_.end();

   while (i != j) {
     const cues_set_t::value_type& v = *i;

     if (time_ns >= 0 && v > time_ns)
       return true;  // nothing else to do just yet

     if (!v.Write(segment_)) {
       printf("\nCould not add metadata.\n");
       return false;  // error
     }

     cues_set_.erase(i++);
   }

   return true;
 }

 bool SampleMuxerMetadata::LoadChapters(const char* file) {
   if (!chapter_cues_.empty()) {
     printf("Support for more than one chapters file is not yet implemented\n");
     return false;
   }

   cue_list_t cues;

   if (!ParseChapters(file, &cues))
     return false;

   // TODO(matthewjheaney): support more than one chapters file
   chapter_cues_.swap(cues);

   return true;
 }

 bool SampleMuxerMetadata::ParseChapters(const char* file,
                                         cue_list_t* cues_ptr) {
   cue_list_t& cues = *cues_ptr;
   cues.clear();

   libwebvtt::VttReader r;
   int e = r.Open(file);

   if (e) {
     printf("Unable to open WebVTT file: \"%s\"\n", file);
     return false;
   }

   libwebvtt::Parser p(&r);
   e = p.Init();

   if (e < 0) {  // error
     printf("Error parsing WebVTT file: \"%s\"\n", file);
     return false;
   }

   libwebvtt::Time t;
   t.hours = -1;

   for (;;) {
     cue_t c;
     e = p.Parse(&c);

     if (e < 0) {  // error
       printf("Error parsing WebVTT file: \"%s\"\n", file);
       return false;
     }

     if (e > 0)  // EOF
       return true;

     if (c.start_time < t) {
       printf("bad WebVTT cue timestamp (out-of-order)\n");
       return false;
     }

     if (c.stop_time < c.start_time) {
       printf("bad WebVTT cue timestamp (stop < start)\n");
       return false;
     }

     t = c.start_time;
     cues.push_back(c);
   }
 }

 bool SampleMuxerMetadata::AddChapter(const cue_t& cue) {
   // TODO(matthewjheaney): support language and country

   mkvmuxer::Chapter* const chapter = segment_->AddChapter();

   if (chapter == NULL) {
     printf("Unable to add chapter\n");
     return false;
   }

   if (cue.identifier.empty()) {
     chapter->set_id(NULL);
   } else {
     const char* const id = cue.identifier.c_str();
     if (!chapter->set_id(id)) {
       printf("Unable to set chapter id\n");
       return false;
     }
   }

   typedef libwebvtt::presentation_t time_ms_t;
   const time_ms_t start_time_ms = cue.start_time.presentation();
   const time_ms_t stop_time_ms = cue.stop_time.presentation();

   enum { kNsPerMs = 1000000 };
   const uint64_t start_time_ns = start_time_ms * kNsPerMs;
   const uint64_t stop_time_ns = stop_time_ms * kNsPerMs;

   chapter->set_time(*segment_, start_time_ns, stop_time_ns);

   typedef libwebvtt::Cue::payload_t::const_iterator iter_t;
   iter_t i = cue.payload.begin();
   const iter_t j = cue.payload.end();

   std::string title;

   for (;;) {
     title += *i++;

     if (i == j)
       break;

     enum { kLF = '\x0A' };
     title += kLF;
   }

   if (!chapter->add_string(title.c_str(), NULL, NULL)) {
     printf("Unable to set chapter title\n");
     return false;
   }

   return true;
 }

 bool SampleMuxerMetadata::AddTrack(Kind kind, uint64_t* track_num) {
   *track_num = 0;

   // Track number value 0 means "let muxer choose track number"
   mkvmuxer::Track* const track = segment_->AddTrack(0);

   if (track == NULL)  // error
     return false;

   // Return the track number value chosen by the muxer
   *track_num = track->number();

   int type;
   const char* codec_id;

   switch (kind) {
     case kSubtitles:
       type = 0x11;
       codec_id = "D_WEBVTT/SUBTITLES";
       break;

     case kCaptions:
       type = 0x11;
       codec_id = "D_WEBVTT/CAPTIONS";
       break;

     case kDescriptions:
       type = 0x21;
       codec_id = "D_WEBVTT/DESCRIPTIONS";
       break;

     case kMetadata:
       type = 0x21;
       codec_id = "D_WEBVTT/METADATA";
       break;

     default:
       return false;
   }

   track->set_type(type);
   track->set_codec_id(codec_id);

   // TODO(matthewjheaney): set name and language

   return true;
 }

 bool SampleMuxerMetadata::Parse(const char* file, Kind /* kind */,
                                 uint64_t track_num) {
   libwebvtt::VttReader r;
   int e = r.Open(file);

   if (e) {
     printf("Unable to open WebVTT file: \"%s\"\n", file);
     return false;
   }

   libwebvtt::Parser p(&r);

   e = p.Init();

   if (e < 0) {  // error
     printf("Error parsing WebVTT file: \"%s\"\n", file);
     return false;
   }

   SortableCue cue;
   cue.track_num = track_num;

   libwebvtt::Time t;
   t.hours = -1;

   for (;;) {
     cue_t& c = cue.cue;
     e = p.Parse(&c);

     if (e < 0) {  // error
       printf("Error parsing WebVTT file: \"%s\"\n", file);
       return false;
     }

     if (e > 0)  // EOF
       return true;

     if (c.start_time >= t) {
       t = c.start_time;
     } else {
       printf("bad WebVTT cue timestamp (out-of-order)\n");
       return false;
     }

     if (c.stop_time < c.start_time) {
       printf("bad WebVTT cue timestamp (stop < start)\n");
       return false;
     }

     cues_set_.insert(cue);
   }
 }

 void SampleMuxerMetadata::MakeFrame(const cue_t& c, std::string* pf) {
   pf->clear();
   WriteCueIdentifier(c.identifier, pf);
   WriteCueSettings(c.settings, pf);
   WriteCuePayload(c.payload, pf);
 }

 void SampleMuxerMetadata::WriteCueIdentifier(const std::string& identifier,
                                              std::string* pf) {
   pf->append(identifier);
   pf->push_back('\x0A');  // LF
 }

 void SampleMuxerMetadata::WriteCueSettings(const cue_t::settings_t& settings,
                                            std::string* pf) {
   if (settings.empty()) {
     pf->push_back('\x0A');  // LF
     return;
   }

   typedef cue_t::settings_t::const_iterator iter_t;

   iter_t i = settings.begin();
   const iter_t j = settings.end();

   for (;;) {
     const libwebvtt::Setting& setting = *i++;

     pf->append(setting.name);
     pf->push_back(':');
     pf->append(setting.value);

     if (i == j)
       break;

     pf->push_back(' ');  // separate settings with whitespace
   }

   pf->push_back('\x0A');  // LF
 }

 void SampleMuxerMetadata::WriteCuePayload(const cue_t::payload_t& payload,
                                           std::string* pf) {
   typedef cue_t::payload_t::const_iterator iter_t;

   iter_t i = payload.begin();
   const iter_t j = payload.end();

   while (i != j) {
     const std::string& line = *i++;
     pf->append(line);
     pf->push_back('\x0A');  // LF
   }
 }

 bool SampleMuxerMetadata::SortableCue::Write(mkvmuxer::Segment* segment) const {
   // Cue start time expressed in milliseconds
   const int64_t start_ms = cue.start_time.presentation();

   // Cue start time expressed in nanoseconds (MKV time)
   const int64_t start_ns = start_ms * 1000000;

   // Cue stop time expressed in milliseconds
   const int64_t stop_ms = cue.stop_time.presentation();

   // Cue stop time expressed in nanonseconds
   const int64_t stop_ns = stop_ms * 1000000;

   // Metadata blocks always specify the block duration.
   const int64_t duration_ns = stop_ns - start_ns;

   std::string frame;
   MakeFrame(cue, &frame);

   typedef const uint8_t* data_t;
   const data_t buf = reinterpret_cast<data_t>(frame.data());
   const uint64_t len = frame.length();

   mkvmuxer::Frame muxer_frame;
   if (!muxer_frame.Init(buf, len))
     return 0;
   muxer_frame.set_track_number(track_num);
   muxer_frame.set_timestamp(start_ns);
   muxer_frame.set_duration(duration_ns);
   muxer_frame.set_is_key(true);  // All metadata frames are keyframes.
   return segment->AddGenericFrame(&muxer_frame);
 }
	// Copyright (c) 2012 The WebM project authors. All Rights Reserved.
	//
	// Use of this source code is governed by a BSD-style license
	// that can be found in the LICENSE file in the root of the source
	// tree. An additional intellectual property rights grant can be found
	// in the file PATENTS. All contributing project authors may
	// be found in the AUTHORS file in the root of the source tree.
	//
	// This sample application demonstrates how to use the matroska parser
	// library, which allows clients to handle a matroska format file.

	#include "sample_muxer_metadata.h"

	#include <cstdio>
	#include <string>

	#include "mkvmuxer/mkvmuxer.h"
	#include "webvtt/vttreader.h"

	SampleMuxerMetadata::SampleMuxerMetadata() : segment_(NULL) {}

	bool SampleMuxerMetadata::Init(mkvmuxer::Segment* segment) {
	if (segment == NULL \|\| segment_ != NULL)
	return false;

	segment_ = segment;
	return true;
	}

	bool SampleMuxerMetadata::Load(const char* file, Kind kind) {
	if (kind == kChapters)
	return LoadChapters(file);

	uint64_t track_num;

	if (!AddTrack(kind, &track_num)) {
	printf("Unable to add track for WebVTT file \"%s\"\n", file);
	return false;
	}

	return Parse(file, kind, track_num);
	}

	bool SampleMuxerMetadata::AddChapters() {
	typedef cue_list_t::const_iterator iter_t;
	iter_t i = chapter_cues_.begin();
	const iter_t j = chapter_cues_.end();

	while (i != j) {
	const cue_t& chapter = *i++;

	if (!AddChapter(chapter))
	return false;
	}

	return true;
	}

	bool SampleMuxerMetadata::Write(int64_t time_ns) {
	typedef cues_set_t::iterator iter_t;

	iter_t i = cues_set_.begin();
	const iter_t j = cues_set_.end();

	while (i != j) {
	const cues_set_t::value_type& v = *i;

	if (time_ns >= 0 && v > time_ns)
	return true; // nothing else to do just yet

	if (!v.Write(segment_)) {
	printf("\nCould not add metadata.\n");
	return false; // error
	}

	cues_set_.erase(i++);
	}

	return true;
	}

	bool SampleMuxerMetadata::LoadChapters(const char* file) {
	if (!chapter_cues_.empty()) {
	printf("Support for more than one chapters file is not yet implemented\n");
	return false;
	}

	cue_list_t cues;

	if (!ParseChapters(file, &cues))
	return false;

	// TODO(matthewjheaney): support more than one chapters file
	chapter_cues_.swap(cues);

	return true;
	}

	bool SampleMuxerMetadata::ParseChapters(const char* file,
	cue_list_t* cues_ptr) {
	cue_list_t& cues = *cues_ptr;
	cues.clear();

	libwebvtt::VttReader r;
	int e = r.Open(file);

	if (e) {
	printf("Unable to open WebVTT file: \"%s\"\n", file);
	return false;
	}

	libwebvtt::Parser p(&r);
	e = p.Init();

	if (e < 0) { // error
	printf("Error parsing WebVTT file: \"%s\"\n", file);
	return false;
	}

	libwebvtt::Time t;
	t.hours = -1;

	for (;;) {
	cue_t c;
	e = p.Parse(&c);

	if (e < 0) { // error
	printf("Error parsing WebVTT file: \"%s\"\n", file);
	return false;
	}

	if (e > 0) // EOF
	return true;

	if (c.start_time < t) {
	printf("bad WebVTT cue timestamp (out-of-order)\n");
	return false;
	}

	if (c.stop_time < c.start_time) {
	printf("bad WebVTT cue timestamp (stop < start)\n");
	return false;
	}

	t = c.start_time;
	cues.push_back(c);
	}
	}

	bool SampleMuxerMetadata::AddChapter(const cue_t& cue) {
	// TODO(matthewjheaney): support language and country

	mkvmuxer::Chapter* const chapter = segment_->AddChapter();

	if (chapter == NULL) {
	printf("Unable to add chapter\n");
	return false;
	}

	if (cue.identifier.empty()) {
	chapter->set_id(NULL);
	} else {
	const char* const id = cue.identifier.c_str();
	if (!chapter->set_id(id)) {
	printf("Unable to set chapter id\n");
	return false;
	}
	}

	typedef libwebvtt::presentation_t time_ms_t;
	const time_ms_t start_time_ms = cue.start_time.presentation();
	const time_ms_t stop_time_ms = cue.stop_time.presentation();

	enum { kNsPerMs = 1000000 };
	const uint64_t start_time_ns = start_time_ms * kNsPerMs;
	const uint64_t stop_time_ns = stop_time_ms * kNsPerMs;

	chapter->set_time(*segment_, start_time_ns, stop_time_ns);

	typedef libwebvtt::Cue::payload_t::const_iterator iter_t;
	iter_t i = cue.payload.begin();
	const iter_t j = cue.payload.end();

	std::string title;

	for (;;) {
	title += *i++;

	if (i == j)
	break;

	enum { kLF = '\x0A' };
	title += kLF;
	}

	if (!chapter->add_string(title.c_str(), NULL, NULL)) {
	printf("Unable to set chapter title\n");
	return false;
	}

	return true;
	}

	bool SampleMuxerMetadata::AddTrack(Kind kind, uint64_t* track_num) {
	*track_num = 0;

	// Track number value 0 means "let muxer choose track number"
	mkvmuxer::Track* const track = segment_->AddTrack(0);

	if (track == NULL) // error
	return false;

	// Return the track number value chosen by the muxer
	*track_num = track->number();

	int type;
	const char* codec_id;

	switch (kind) {
	case kSubtitles:
	type = 0x11;
	codec_id = "D_WEBVTT/SUBTITLES";
	break;

	case kCaptions:
	type = 0x11;
	codec_id = "D_WEBVTT/CAPTIONS";
	break;

	case kDescriptions:
	type = 0x21;
	codec_id = "D_WEBVTT/DESCRIPTIONS";
	break;

	case kMetadata:
	type = 0x21;
	codec_id = "D_WEBVTT/METADATA";
	break;

	default:
	return false;
	}

	track->set_type(type);
	track->set_codec_id(codec_id);

	// TODO(matthewjheaney): set name and language

	return true;
	}

	bool SampleMuxerMetadata::Parse(const char* file, Kind /* kind */,
	uint64_t track_num) {
	libwebvtt::VttReader r;
	int e = r.Open(file);

	if (e) {
	printf("Unable to open WebVTT file: \"%s\"\n", file);
	return false;
	}

	libwebvtt::Parser p(&r);

	e = p.Init();

	if (e < 0) { // error
	printf("Error parsing WebVTT file: \"%s\"\n", file);
	return false;
	}

	SortableCue cue;
	cue.track_num = track_num;

	libwebvtt::Time t;
	t.hours = -1;

	for (;;) {
	cue_t& c = cue.cue;
	e = p.Parse(&c);

	if (e < 0) { // error
	printf("Error parsing WebVTT file: \"%s\"\n", file);
	return false;
	}

	if (e > 0) // EOF
	return true;

	if (c.start_time >= t) {
	t = c.start_time;
	} else {
	printf("bad WebVTT cue timestamp (out-of-order)\n");
	return false;
	}

	if (c.stop_time < c.start_time) {
	printf("bad WebVTT cue timestamp (stop < start)\n");
	return false;
	}

	cues_set_.insert(cue);
	}
	}

	void SampleMuxerMetadata::MakeFrame(const cue_t& c, std::string* pf) {
	pf->clear();
	WriteCueIdentifier(c.identifier, pf);
	WriteCueSettings(c.settings, pf);
	WriteCuePayload(c.payload, pf);
	}

	void SampleMuxerMetadata::WriteCueIdentifier(const std::string& identifier,
	std::string* pf) {
	pf->append(identifier);
	pf->push_back('\x0A'); // LF
	}

	void SampleMuxerMetadata::WriteCueSettings(const cue_t::settings_t& settings,
	std::string* pf) {
	if (settings.empty()) {
	pf->push_back('\x0A'); // LF
	return;
	}

	typedef cue_t::settings_t::const_iterator iter_t;

	iter_t i = settings.begin();
	const iter_t j = settings.end();

	for (;;) {
	const libwebvtt::Setting& setting = *i++;

	pf->append(setting.name);
	pf->push_back(':');
	pf->append(setting.value);

	if (i == j)
	break;

	pf->push_back(' '); // separate settings with whitespace
	}

	pf->push_back('\x0A'); // LF
	}

	void SampleMuxerMetadata::WriteCuePayload(const cue_t::payload_t& payload,
	std::string* pf) {
	typedef cue_t::payload_t::const_iterator iter_t;

	iter_t i = payload.begin();
	const iter_t j = payload.end();

	while (i != j) {
	const std::string& line = *i++;
	pf->append(line);
	pf->push_back('\x0A'); // LF
	}
	}

	bool SampleMuxerMetadata::SortableCue::Write(mkvmuxer::Segment* segment) const {
	// Cue start time expressed in milliseconds
	const int64_t start_ms = cue.start_time.presentation();

	// Cue start time expressed in nanoseconds (MKV time)
	const int64_t start_ns = start_ms * 1000000;

	// Cue stop time expressed in milliseconds
	const int64_t stop_ms = cue.stop_time.presentation();

	// Cue stop time expressed in nanonseconds
	const int64_t stop_ns = stop_ms * 1000000;

	// Metadata blocks always specify the block duration.
	const int64_t duration_ns = stop_ns - start_ns;

	std::string frame;
	MakeFrame(cue, &frame);

	typedef const uint8_t* data_t;
	const data_t buf = reinterpret_cast<data_t>(frame.data());
	const uint64_t len = frame.length();

	mkvmuxer::Frame muxer_frame;
	if (!muxer_frame.Init(buf, len))
	return 0;
	muxer_frame.set_track_number(track_num);
	muxer_frame.set_timestamp(start_ns);
	muxer_frame.set_duration(duration_ns);
	muxer_frame.set_is_key(true); // All metadata frames are keyframes.
	return segment->AddGenericFrame(&muxer_frame);
	}