m2ts/webm2pes.cc - platform/external/libwebm - Git at Google

 // Copyright (c) 2015 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.
 #include "m2ts/webm2pes.h"

 #include <algorithm>
 #include <cassert>
 #include <cstdio>
 #include <cstring>
 #include <new>
 #include <vector>

 #include "common/libwebm_util.h"

 namespace libwebm {

 const std::size_t Webm2Pes::kMaxPayloadSize = 32768;

 //
 // PesOptionalHeader methods.
 //

 void PesOptionalHeader::SetPtsBits(std::int64_t pts_90khz) {
   std::uint64_t* pts_bits = &pts.bits;
   *pts_bits = 0;

   // PTS is broken up and stored in 40 bits as shown:
   //
   //  PES PTS Only flag
   // /                  Marker              Marker              Marker
   // |                 /                   /                   /
   // |                 |                   |                   |
   // 7654  321         0  765432107654321  0  765432107654321  0
   // 0010  PTS 32-30   1  PTS 29-15        1  PTS 14-0         1
   const std::uint32_t pts1 = (pts_90khz >> 30) & 0x7;
   const std::uint32_t pts2 = (pts_90khz >> 15) & 0x7FFF;
   const std::uint32_t pts3 = pts_90khz & 0x7FFF;

   std::uint8_t buffer[5] = {0};
   // PTS only flag.
   buffer[0] |= 1 << 5;
   // Top 3 bits of PTS and 1 bit marker.
   buffer[0] |= pts1 << 1;
   // Marker.
   buffer[0] |= 1;

   // Next 15 bits of pts and 1 bit marker.
   // Top 8 bits of second PTS chunk.
   buffer[1] |= (pts2 >> 7) & 0xff;
   // bottom 7 bits of second PTS chunk.
   buffer[2] |= (pts2 << 1);
   // Marker.
   buffer[2] |= 1;

   // Last 15 bits of pts and 1 bit marker.
   // Top 8 bits of second PTS chunk.
   buffer[3] |= (pts3 >> 7) & 0xff;
   // bottom 7 bits of second PTS chunk.
   buffer[4] |= (pts3 << 1);
   // Marker.
   buffer[4] |= 1;

   // Write bits into PesHeaderField.
   std::memcpy(reinterpret_cast<std::uint8_t*>(pts_bits), buffer, 5);
 }

 // Writes fields to |buffer| and returns true. Returns false when write or
 // field value validation fails.
 bool PesOptionalHeader::Write(bool write_pts, PacketDataBuffer* buffer) const {
   if (buffer == nullptr) {
     std::fprintf(stderr, "Webm2Pes: nullptr in opt header writer.\n");
     return false;
   }

   const int kHeaderSize = 9;
   std::uint8_t header[kHeaderSize] = {0};
   std::uint8_t* byte = header;

   if (marker.Check() != true || scrambling.Check() != true ||
       priority.Check() != true || data_alignment.Check() != true ||
       copyright.Check() != true || original.Check() != true ||
       has_pts.Check() != true || has_dts.Check() != true ||
       pts.Check() != true || stuffing_byte.Check() != true) {
     std::fprintf(stderr, "Webm2Pes: Invalid PES Optional Header field.\n");
     return false;
   }

   // TODO(tomfinegan): As noted in above, the PesHeaderFields should be an
   // array (or some data structure) that can be iterated over.

   // First byte of header, fields: marker, scrambling, priority, alignment,
   // copyright, original.
   *byte = 0;
   *byte |= marker.bits << marker.shift;
   *byte |= scrambling.bits << scrambling.shift;
   *byte |= priority.bits << priority.shift;
   *byte |= data_alignment.bits << data_alignment.shift;
   *byte |= copyright.bits << copyright.shift;
   *byte |= original.bits << original.shift;

   // Second byte of header, fields: has_pts, has_dts, unused fields.
   *++byte = 0;
   if (write_pts == true)
     *byte |= has_pts.bits << has_pts.shift;

   *byte |= has_dts.bits << has_dts.shift;

   // Third byte of header, fields: remaining size of header.
   *++byte = remaining_size.bits & 0xff;  // Field is 8 bits wide.

   int num_stuffing_bytes =
       (pts.num_bits + 7) / 8 + 1 /* always 1 stuffing byte */;
   if (write_pts == true) {
     // Write the PTS value as big endian and adjust stuffing byte count
     // accordingly.
     *++byte = pts.bits & 0xff;
     *++byte = (pts.bits >> 8) & 0xff;
     *++byte = (pts.bits >> 16) & 0xff;
     *++byte = (pts.bits >> 24) & 0xff;
     *++byte = (pts.bits >> 32) & 0xff;
     num_stuffing_bytes = 1;
   }

   // Add the stuffing byte(s).
   for (int i = 0; i < num_stuffing_bytes; ++i)
     *++byte = stuffing_byte.bits & 0xff;

   return CopyAndEscapeStartCodes(&header[0], kHeaderSize, buffer);
 }

 //
 // BCMVHeader methods.
 //

 bool BCMVHeader::Write(PacketDataBuffer* buffer) const {
   if (buffer == nullptr) {
     std::fprintf(stderr, "Webm2Pes: nullptr for buffer in BCMV Write.\n");
     return false;
   }
   const int kBcmvSize = 4;
   for (int i = 0; i < kBcmvSize; ++i)
     buffer->push_back(bcmv[i]);

   // Note: The 4 byte length field must include the size of the BCMV header.
   const int kRemainingBytes = 6;
   const uint32_t bcmv_total_length = length + static_cast<uint32_t>(size());
   const uint8_t bcmv_buffer[kRemainingBytes] = {
       static_cast<std::uint8_t>((bcmv_total_length >> 24) & 0xff),
       static_cast<std::uint8_t>((bcmv_total_length >> 16) & 0xff),
       static_cast<std::uint8_t>((bcmv_total_length >> 8) & 0xff),
       static_cast<std::uint8_t>(bcmv_total_length & 0xff),
       0,
       0 /* 2 bytes 0 padding */};

   return CopyAndEscapeStartCodes(bcmv_buffer, kRemainingBytes, buffer);
 }

 //
 // PesHeader methods.
 //

 // Writes out the header to |buffer|. Calls PesOptionalHeader::Write() to write
 // |optional_header| contents. Returns true when successful, false otherwise.
 bool PesHeader::Write(bool write_pts, PacketDataBuffer* buffer) const {
   if (buffer == nullptr) {
     std::fprintf(stderr, "Webm2Pes: nullptr in header writer.\n");
     return false;
   }

   // Write |start_code|.
   const int kStartCodeLength = 4;
   for (int i = 0; i < kStartCodeLength; ++i)
     buffer->push_back(start_code[i]);

   // The length field here reports number of bytes following the field. The
   // length of the optional header must be added to the payload length set by
   // the user.
   const std::size_t header_length =
       packet_length + optional_header.size_in_bytes();
   if (header_length > UINT16_MAX)
     return false;

   // Write |header_length| as big endian.
   std::uint8_t byte = (header_length >> 8) & 0xff;
   buffer->push_back(byte);
   byte = header_length & 0xff;
   buffer->push_back(byte);

   // Write the (not really) optional header.
   if (optional_header.Write(write_pts, buffer) != true) {
     std::fprintf(stderr, "Webm2Pes: PES optional header write failed.");
     return false;
   }
   return true;
 }

 //
 // Webm2Pes methods.
 //

 bool Webm2Pes::ConvertToFile() {
   if (input_file_name_.empty() || output_file_name_.empty()) {
     std::fprintf(stderr, "Webm2Pes: input and/or output file name(s) empty.\n");
     return false;
   }

   output_file_ = FilePtr(fopen(output_file_name_.c_str(), "wb"), FILEDeleter());
   if (output_file_ == nullptr) {
     std::fprintf(stderr, "Webm2Pes: Cannot open %s for output.\n",
                  output_file_name_.c_str());
     return false;
   }

   if (InitWebmParser() != true) {
     std::fprintf(stderr, "Webm2Pes: Cannot initialize WebM parser.\n");
     return false;
   }

   // Walk clusters in segment.
   const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
   while (cluster != nullptr && cluster->EOS() == false) {
     const mkvparser::BlockEntry* block_entry = nullptr;
     std::int64_t block_status = cluster->GetFirst(block_entry);
     if (block_status < 0) {
       std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
                    input_file_name_.c_str());
       return false;
     }

     // Walk blocks in cluster.
     while (block_entry != nullptr && block_entry->EOS() == false) {
       const mkvparser::Block* block = block_entry->GetBlock();
       if (block->GetTrackNumber() == video_track_num_) {
         const int frame_count = block->GetFrameCount();

         // Walk frames in block.
         for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
           const mkvparser::Block::Frame& mkvparser_frame =
               block->GetFrame(frame_num);

           // Read the frame.
           VideoFrame vpx_frame(block->GetTime(cluster), codec_);
           if (ReadVideoFrame(mkvparser_frame, &vpx_frame) == false) {
             fprintf(stderr, "Webm2Pes: frame read failed.\n");
             return false;
           }

           // Write frame out as PES packet(s).
           if (WritePesPacket(vpx_frame, &packet_data_) == false) {
             std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
             return false;
           }

           // Write contents of |packet_data_| to |output_file_|.
           if (std::fwrite(&packet_data_[0], 1, packet_data_.size(),
                           output_file_.get()) != packet_data_.size()) {
             std::fprintf(stderr, "Webm2Pes: packet payload write failed.\n");
             return false;
           }
           bytes_written_ += packet_data_.size();
         }
       }
       block_status = cluster->GetNext(block_entry, block_entry);
       if (block_status < 0) {
         std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
                      input_file_name_.c_str());
         return false;
       }
     }

     cluster = webm_parser_->GetNext(cluster);
   }

   std::fflush(output_file_.get());
   return true;
 }

 bool Webm2Pes::ConvertToPacketReceiver() {
   if (input_file_name_.empty() || packet_sink_ == nullptr) {
     std::fprintf(stderr, "Webm2Pes: input file name empty or null sink.\n");
     return false;
   }

   if (InitWebmParser() != true) {
     std::fprintf(stderr, "Webm2Pes: Cannot initialize WebM parser.\n");
     return false;
   }

   // Walk clusters in segment.
   const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
   while (cluster != nullptr && cluster->EOS() == false) {
     const mkvparser::BlockEntry* block_entry = nullptr;
     std::int64_t block_status = cluster->GetFirst(block_entry);
     if (block_status < 0) {
       std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
                    input_file_name_.c_str());
       return false;
     }

     // Walk blocks in cluster.
     while (block_entry != nullptr && block_entry->EOS() == false) {
       const mkvparser::Block* block = block_entry->GetBlock();
       if (block->GetTrackNumber() == video_track_num_) {
         const int frame_count = block->GetFrameCount();

         // Walk frames in block.
         for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
           const mkvparser::Block::Frame& mkvparser_frame =
               block->GetFrame(frame_num);

           // Read the frame.
           VideoFrame frame(block->GetTime(cluster), codec_);
           if (ReadVideoFrame(mkvparser_frame, &frame) == false) {
             fprintf(stderr, "Webm2Pes: frame read failed.\n");
             return false;
           }

           // Write frame out as PES packet(s).
           if (WritePesPacket(frame, &packet_data_) == false) {
             std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
             return false;
           }
           if (packet_sink_->ReceivePacket(packet_data_) != true) {
             std::fprintf(stderr, "Webm2Pes: ReceivePacket failed.\n");
             return false;
           }
           bytes_written_ += packet_data_.size();
         }
       }
       block_status = cluster->GetNext(block_entry, block_entry);
       if (block_status < 0) {
         std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
                      input_file_name_.c_str());
         return false;
       }
     }

     cluster = webm_parser_->GetNext(cluster);
   }

   return true;
 }

 bool Webm2Pes::InitWebmParser() {
   if (webm_reader_.Open(input_file_name_.c_str()) != 0) {
     std::fprintf(stderr, "Webm2Pes: Cannot open %s as input.\n",
                  input_file_name_.c_str());
     return false;
   }

   using mkvparser::Segment;
   Segment* webm_parser = nullptr;
   if (Segment::CreateInstance(&webm_reader_, 0 /* pos */,
                               webm_parser /* Segment*& */) != 0) {
     std::fprintf(stderr, "Webm2Pes: Cannot create WebM parser.\n");
     return false;
   }
   webm_parser_.reset(webm_parser);

   if (webm_parser_->Load() != 0) {
     std::fprintf(stderr, "Webm2Pes: Cannot parse %s.\n",
                  input_file_name_.c_str());
     return false;
   }

   // Make sure there's a video track.
   const mkvparser::Tracks* tracks = webm_parser_->GetTracks();
   if (tracks == nullptr) {
     std::fprintf(stderr, "Webm2Pes: %s has no tracks.\n",
                  input_file_name_.c_str());
     return false;
   }

   timecode_scale_ = webm_parser_->GetInfo()->GetTimeCodeScale();

   for (int track_index = 0;
        track_index < static_cast<int>(tracks->GetTracksCount());
        ++track_index) {
     const mkvparser::Track* track = tracks->GetTrackByIndex(track_index);
     if (track && track->GetType() == mkvparser::Track::kVideo) {
       if (std::string(track->GetCodecId()) == std::string("V_VP8")) {
         codec_ = VideoFrame::kVP8;
       } else if (std::string(track->GetCodecId()) == std::string("V_VP9")) {
         codec_ = VideoFrame::kVP9;
       } else {
         fprintf(stderr, "Webm2Pes: Codec must be VP8 or VP9.\n");
         return false;
       }
       video_track_num_ = track_index + 1;
       break;
     }
   }
   if (video_track_num_ < 1) {
     std::fprintf(stderr, "Webm2Pes: No video track found in %s.\n",
                  input_file_name_.c_str());
     return false;
   }
   return true;
 }

 bool Webm2Pes::ReadVideoFrame(const mkvparser::Block::Frame& mkvparser_frame,
                               VideoFrame* frame) {
   if (mkvparser_frame.len < 1 || frame == nullptr)
     return false;

   const std::size_t mkv_len = static_cast<std::size_t>(mkvparser_frame.len);
   if (mkv_len > frame->buffer().capacity) {
     const std::size_t new_size = 2 * mkv_len;
     if (frame->Init(new_size) == false) {
       std::fprintf(stderr, "Webm2Pes: Out of memory.\n");
       return false;
     }
   }
   if (mkvparser_frame.Read(&webm_reader_, frame->buffer().data.get()) != 0) {
     std::fprintf(stderr, "Webm2Pes: Error reading VPx frame!\n");
     return false;
   }
   return frame->SetBufferLength(mkv_len);
 }

 bool Webm2Pes::WritePesPacket(const VideoFrame& frame,
                               PacketDataBuffer* packet_data) {
   if (frame.buffer().data.get() == nullptr || frame.buffer().length < 1)
     return false;

   Ranges frame_ranges;
   if (frame.codec() == VideoFrame::kVP9) {
     bool error = false;
     const bool has_superframe_index =
         ParseVP9SuperFrameIndex(frame.buffer().data.get(),
                                 frame.buffer().length, &frame_ranges, &error);
     if (error) {
       std::fprintf(stderr, "Webm2Pes: Superframe index parse failed.\n");
       return false;
     }
     if (has_superframe_index == false) {
       frame_ranges.push_back(Range(0, frame.buffer().length));
     }
   } else {
     frame_ranges.push_back(Range(0, frame.buffer().length));
   }

   const std::int64_t khz90_pts =
       NanosecondsTo90KhzTicks(frame.nanosecond_pts());
   PesHeader header;
   header.optional_header.SetPtsBits(khz90_pts);

   packet_data->clear();

   for (const Range& packet_payload_range : frame_ranges) {
     std::size_t extra_bytes = 0;
     if (packet_payload_range.length > kMaxPayloadSize) {
       extra_bytes = packet_payload_range.length - kMaxPayloadSize;
     }
     if (packet_payload_range.length + packet_payload_range.offset >
         frame.buffer().length) {
       std::fprintf(stderr, "Webm2Pes: Invalid frame length.\n");
       return false;
     }

     // First packet of new frame. Always include PTS and BCMV header.
     header.packet_length =
         packet_payload_range.length - extra_bytes + BCMVHeader::size();
     if (header.Write(true, packet_data) != true) {
       std::fprintf(stderr, "Webm2Pes: packet header write failed.\n");
       return false;
     }

     BCMVHeader bcmv_header(static_cast<uint32_t>(packet_payload_range.length));
     if (bcmv_header.Write(packet_data) != true) {
       std::fprintf(stderr, "Webm2Pes: BCMV write failed.\n");
       return false;
     }

     // Insert the payload at the end of |packet_data|.
     const std::uint8_t* const payload_start =
         frame.buffer().data.get() + packet_payload_range.offset;

     const std::size_t bytes_to_copy = packet_payload_range.length - extra_bytes;
     if (CopyAndEscapeStartCodes(payload_start, bytes_to_copy, packet_data) ==
         false) {
       fprintf(stderr, "Webm2Pes: Payload write failed.\n");
       return false;
     }

     std::size_t bytes_copied = bytes_to_copy;
     while (extra_bytes) {
       // Write PES packets for the remaining data, but omit the PTS and BCMV
       // header.
       const std::size_t extra_bytes_to_copy =
           std::min(kMaxPayloadSize, extra_bytes);
       extra_bytes -= extra_bytes_to_copy;
       header.packet_length = extra_bytes_to_copy;
       if (header.Write(false, packet_data) != true) {
         fprintf(stderr, "Webm2pes: fragment write failed.\n");
         return false;
       }

       const std::uint8_t* fragment_start = payload_start + bytes_copied;
       if (CopyAndEscapeStartCodes(fragment_start, extra_bytes_to_copy,
                                   packet_data) == false) {
         fprintf(stderr, "Webm2Pes: Payload write failed.\n");
         return false;
       }

       bytes_copied += extra_bytes_to_copy;
     }
   }

   return true;
 }

 bool CopyAndEscapeStartCodes(const std::uint8_t* raw_input,
                              std::size_t raw_input_length,
                              PacketDataBuffer* packet_buffer) {
   if (raw_input == nullptr || raw_input_length < 1 || packet_buffer == nullptr)
     return false;

   int num_zeros = 0;
   for (std::size_t i = 0; i < raw_input_length; ++i) {
     const uint8_t byte = raw_input[i];

     if (byte == 0) {
       ++num_zeros;
     } else if (num_zeros >= 2 && (byte == 0x1 || byte == 0x3)) {
       packet_buffer->push_back(0x3);
       num_zeros = 0;
     } else {
       num_zeros = 0;
     }

     packet_buffer->push_back(byte);
   }

   return true;
 }

 }  // namespace libwebm
	// Copyright (c) 2015 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.
	#include "m2ts/webm2pes.h"

	#include <algorithm>
	#include <cassert>
	#include <cstdio>
	#include <cstring>
	#include <new>
	#include <vector>

	#include "common/libwebm_util.h"

	namespace libwebm {

	const std::size_t Webm2Pes::kMaxPayloadSize = 32768;

	//
	// PesOptionalHeader methods.
	//

	void PesOptionalHeader::SetPtsBits(std::int64_t pts_90khz) {
	std::uint64_t* pts_bits = &pts.bits;
	*pts_bits = 0;

	// PTS is broken up and stored in 40 bits as shown:
	//
	// PES PTS Only flag
	// / Marker Marker Marker
	// \| / / /
	// \| \| \| \|
	// 7654 321 0 765432107654321 0 765432107654321 0
	// 0010 PTS 32-30 1 PTS 29-15 1 PTS 14-0 1
	const std::uint32_t pts1 = (pts_90khz >> 30) & 0x7;
	const std::uint32_t pts2 = (pts_90khz >> 15) & 0x7FFF;
	const std::uint32_t pts3 = pts_90khz & 0x7FFF;

	std::uint8_t buffer[5] = {0};
	// PTS only flag.
	buffer[0] \|= 1 << 5;
	// Top 3 bits of PTS and 1 bit marker.
	buffer[0] \|= pts1 << 1;
	// Marker.
	buffer[0] \|= 1;

	// Next 15 bits of pts and 1 bit marker.
	// Top 8 bits of second PTS chunk.
	buffer[1] \|= (pts2 >> 7) & 0xff;
	// bottom 7 bits of second PTS chunk.
	buffer[2] \|= (pts2 << 1);
	// Marker.
	buffer[2] \|= 1;

	// Last 15 bits of pts and 1 bit marker.
	// Top 8 bits of second PTS chunk.
	buffer[3] \|= (pts3 >> 7) & 0xff;
	// bottom 7 bits of second PTS chunk.
	buffer[4] \|= (pts3 << 1);
	// Marker.
	buffer[4] \|= 1;

	// Write bits into PesHeaderField.
	std::memcpy(reinterpret_cast<std::uint8_t*>(pts_bits), buffer, 5);
	}

	// Writes fields to \|buffer\| and returns true. Returns false when write or
	// field value validation fails.
	bool PesOptionalHeader::Write(bool write_pts, PacketDataBuffer* buffer) const {
	if (buffer == nullptr) {
	std::fprintf(stderr, "Webm2Pes: nullptr in opt header writer.\n");
	return false;
	}

	const int kHeaderSize = 9;
	std::uint8_t header[kHeaderSize] = {0};
	std::uint8_t* byte = header;

	if (marker.Check() != true \|\| scrambling.Check() != true \|\|
	priority.Check() != true \|\| data_alignment.Check() != true \|\|
	copyright.Check() != true \|\| original.Check() != true \|\|
	has_pts.Check() != true \|\| has_dts.Check() != true \|\|
	pts.Check() != true \|\| stuffing_byte.Check() != true) {
	std::fprintf(stderr, "Webm2Pes: Invalid PES Optional Header field.\n");
	return false;
	}

	// TODO(tomfinegan): As noted in above, the PesHeaderFields should be an
	// array (or some data structure) that can be iterated over.

	// First byte of header, fields: marker, scrambling, priority, alignment,
	// copyright, original.
	*byte = 0;
	*byte \|= marker.bits << marker.shift;
	*byte \|= scrambling.bits << scrambling.shift;
	*byte \|= priority.bits << priority.shift;
	*byte \|= data_alignment.bits << data_alignment.shift;
	*byte \|= copyright.bits << copyright.shift;
	*byte \|= original.bits << original.shift;

	// Second byte of header, fields: has_pts, has_dts, unused fields.
	*++byte = 0;
	if (write_pts == true)
	*byte \|= has_pts.bits << has_pts.shift;

	*byte \|= has_dts.bits << has_dts.shift;

	// Third byte of header, fields: remaining size of header.
	*++byte = remaining_size.bits & 0xff; // Field is 8 bits wide.

	int num_stuffing_bytes =
	(pts.num_bits + 7) / 8 + 1 /* always 1 stuffing byte */;
	if (write_pts == true) {
	// Write the PTS value as big endian and adjust stuffing byte count
	// accordingly.
	*++byte = pts.bits & 0xff;
	*++byte = (pts.bits >> 8) & 0xff;
	*++byte = (pts.bits >> 16) & 0xff;
	*++byte = (pts.bits >> 24) & 0xff;
	*++byte = (pts.bits >> 32) & 0xff;
	num_stuffing_bytes = 1;
	}

	// Add the stuffing byte(s).
	for (int i = 0; i < num_stuffing_bytes; ++i)
	*++byte = stuffing_byte.bits & 0xff;

	return CopyAndEscapeStartCodes(&header[0], kHeaderSize, buffer);
	}

	//
	// BCMVHeader methods.
	//

	bool BCMVHeader::Write(PacketDataBuffer* buffer) const {
	if (buffer == nullptr) {
	std::fprintf(stderr, "Webm2Pes: nullptr for buffer in BCMV Write.\n");
	return false;
	}
	const int kBcmvSize = 4;
	for (int i = 0; i < kBcmvSize; ++i)
	buffer->push_back(bcmv[i]);

	// Note: The 4 byte length field must include the size of the BCMV header.
	const int kRemainingBytes = 6;
	const uint32_t bcmv_total_length = length + static_cast<uint32_t>(size());
	const uint8_t bcmv_buffer[kRemainingBytes] = {
	static_cast<std::uint8_t>((bcmv_total_length >> 24) & 0xff),
	static_cast<std::uint8_t>((bcmv_total_length >> 16) & 0xff),
	static_cast<std::uint8_t>((bcmv_total_length >> 8) & 0xff),
	static_cast<std::uint8_t>(bcmv_total_length & 0xff),
	0,
	0 /* 2 bytes 0 padding */};

	return CopyAndEscapeStartCodes(bcmv_buffer, kRemainingBytes, buffer);
	}

	//
	// PesHeader methods.
	//

	// Writes out the header to \|buffer\|. Calls PesOptionalHeader::Write() to write
	// \|optional_header\| contents. Returns true when successful, false otherwise.
	bool PesHeader::Write(bool write_pts, PacketDataBuffer* buffer) const {
	if (buffer == nullptr) {
	std::fprintf(stderr, "Webm2Pes: nullptr in header writer.\n");
	return false;
	}

	// Write \|start_code\|.
	const int kStartCodeLength = 4;
	for (int i = 0; i < kStartCodeLength; ++i)
	buffer->push_back(start_code[i]);

	// The length field here reports number of bytes following the field. The
	// length of the optional header must be added to the payload length set by
	// the user.
	const std::size_t header_length =
	packet_length + optional_header.size_in_bytes();
	if (header_length > UINT16_MAX)
	return false;

	// Write \|header_length\| as big endian.
	std::uint8_t byte = (header_length >> 8) & 0xff;
	buffer->push_back(byte);
	byte = header_length & 0xff;
	buffer->push_back(byte);

	// Write the (not really) optional header.
	if (optional_header.Write(write_pts, buffer) != true) {
	std::fprintf(stderr, "Webm2Pes: PES optional header write failed.");
	return false;
	}
	return true;
	}

	//
	// Webm2Pes methods.
	//

	bool Webm2Pes::ConvertToFile() {
	if (input_file_name_.empty() \|\| output_file_name_.empty()) {
	std::fprintf(stderr, "Webm2Pes: input and/or output file name(s) empty.\n");
	return false;
	}

	output_file_ = FilePtr(fopen(output_file_name_.c_str(), "wb"), FILEDeleter());
	if (output_file_ == nullptr) {
	std::fprintf(stderr, "Webm2Pes: Cannot open %s for output.\n",
	output_file_name_.c_str());
	return false;
	}

	if (InitWebmParser() != true) {
	std::fprintf(stderr, "Webm2Pes: Cannot initialize WebM parser.\n");
	return false;
	}

	// Walk clusters in segment.
	const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
	while (cluster != nullptr && cluster->EOS() == false) {
	const mkvparser::BlockEntry* block_entry = nullptr;
	std::int64_t block_status = cluster->GetFirst(block_entry);
	if (block_status < 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
	input_file_name_.c_str());
	return false;
	}

	// Walk blocks in cluster.
	while (block_entry != nullptr && block_entry->EOS() == false) {
	const mkvparser::Block* block = block_entry->GetBlock();
	if (block->GetTrackNumber() == video_track_num_) {
	const int frame_count = block->GetFrameCount();

	// Walk frames in block.
	for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
	const mkvparser::Block::Frame& mkvparser_frame =
	block->GetFrame(frame_num);

	// Read the frame.
	VideoFrame vpx_frame(block->GetTime(cluster), codec_);
	if (ReadVideoFrame(mkvparser_frame, &vpx_frame) == false) {
	fprintf(stderr, "Webm2Pes: frame read failed.\n");
	return false;
	}

	// Write frame out as PES packet(s).
	if (WritePesPacket(vpx_frame, &packet_data_) == false) {
	std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
	return false;
	}

	// Write contents of \|packet_data_\| to \|output_file_\|.
	if (std::fwrite(&packet_data_[0], 1, packet_data_.size(),
	output_file_.get()) != packet_data_.size()) {
	std::fprintf(stderr, "Webm2Pes: packet payload write failed.\n");
	return false;
	}
	bytes_written_ += packet_data_.size();
	}
	}
	block_status = cluster->GetNext(block_entry, block_entry);
	if (block_status < 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
	input_file_name_.c_str());
	return false;
	}
	}

	cluster = webm_parser_->GetNext(cluster);
	}

	std::fflush(output_file_.get());
	return true;
	}

	bool Webm2Pes::ConvertToPacketReceiver() {
	if (input_file_name_.empty() \|\| packet_sink_ == nullptr) {
	std::fprintf(stderr, "Webm2Pes: input file name empty or null sink.\n");
	return false;
	}

	if (InitWebmParser() != true) {
	std::fprintf(stderr, "Webm2Pes: Cannot initialize WebM parser.\n");
	return false;
	}

	// Walk clusters in segment.
	const mkvparser::Cluster* cluster = webm_parser_->GetFirst();
	while (cluster != nullptr && cluster->EOS() == false) {
	const mkvparser::BlockEntry* block_entry = nullptr;
	std::int64_t block_status = cluster->GetFirst(block_entry);
	if (block_status < 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot parse first block in %s.\n",
	input_file_name_.c_str());
	return false;
	}

	// Walk blocks in cluster.
	while (block_entry != nullptr && block_entry->EOS() == false) {
	const mkvparser::Block* block = block_entry->GetBlock();
	if (block->GetTrackNumber() == video_track_num_) {
	const int frame_count = block->GetFrameCount();

	// Walk frames in block.
	for (int frame_num = 0; frame_num < frame_count; ++frame_num) {
	const mkvparser::Block::Frame& mkvparser_frame =
	block->GetFrame(frame_num);

	// Read the frame.
	VideoFrame frame(block->GetTime(cluster), codec_);
	if (ReadVideoFrame(mkvparser_frame, &frame) == false) {
	fprintf(stderr, "Webm2Pes: frame read failed.\n");
	return false;
	}

	// Write frame out as PES packet(s).
	if (WritePesPacket(frame, &packet_data_) == false) {
	std::fprintf(stderr, "Webm2Pes: WritePesPacket failed.\n");
	return false;
	}
	if (packet_sink_->ReceivePacket(packet_data_) != true) {
	std::fprintf(stderr, "Webm2Pes: ReceivePacket failed.\n");
	return false;
	}
	bytes_written_ += packet_data_.size();
	}
	}
	block_status = cluster->GetNext(block_entry, block_entry);
	if (block_status < 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot parse block in %s.\n",
	input_file_name_.c_str());
	return false;
	}
	}

	cluster = webm_parser_->GetNext(cluster);
	}

	return true;
	}

	bool Webm2Pes::InitWebmParser() {
	if (webm_reader_.Open(input_file_name_.c_str()) != 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot open %s as input.\n",
	input_file_name_.c_str());
	return false;
	}

	using mkvparser::Segment;
	Segment* webm_parser = nullptr;
	if (Segment::CreateInstance(&webm_reader_, 0 /* pos */,
	webm_parser /* Segment& /) != 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot create WebM parser.\n");
	return false;
	}
	webm_parser_.reset(webm_parser);

	if (webm_parser_->Load() != 0) {
	std::fprintf(stderr, "Webm2Pes: Cannot parse %s.\n",
	input_file_name_.c_str());
	return false;
	}

	// Make sure there's a video track.
	const mkvparser::Tracks* tracks = webm_parser_->GetTracks();
	if (tracks == nullptr) {
	std::fprintf(stderr, "Webm2Pes: %s has no tracks.\n",
	input_file_name_.c_str());
	return false;
	}

	timecode_scale_ = webm_parser_->GetInfo()->GetTimeCodeScale();

	for (int track_index = 0;
	track_index < static_cast<int>(tracks->GetTracksCount());
	++track_index) {
	const mkvparser::Track* track = tracks->GetTrackByIndex(track_index);
	if (track && track->GetType() == mkvparser::Track::kVideo) {
	if (std::string(track->GetCodecId()) == std::string("V_VP8")) {
	codec_ = VideoFrame::kVP8;
	} else if (std::string(track->GetCodecId()) == std::string("V_VP9")) {
	codec_ = VideoFrame::kVP9;
	} else {
	fprintf(stderr, "Webm2Pes: Codec must be VP8 or VP9.\n");
	return false;
	}
	video_track_num_ = track_index + 1;
	break;
	}
	}
	if (video_track_num_ < 1) {
	std::fprintf(stderr, "Webm2Pes: No video track found in %s.\n",
	input_file_name_.c_str());
	return false;
	}
	return true;
	}

	bool Webm2Pes::ReadVideoFrame(const mkvparser::Block::Frame& mkvparser_frame,
	VideoFrame* frame) {
	if (mkvparser_frame.len < 1 \|\| frame == nullptr)
	return false;

	const std::size_t mkv_len = static_cast<std::size_t>(mkvparser_frame.len);
	if (mkv_len > frame->buffer().capacity) {
	const std::size_t new_size = 2 * mkv_len;
	if (frame->Init(new_size) == false) {
	std::fprintf(stderr, "Webm2Pes: Out of memory.\n");
	return false;
	}
	}
	if (mkvparser_frame.Read(&webm_reader_, frame->buffer().data.get()) != 0) {
	std::fprintf(stderr, "Webm2Pes: Error reading VPx frame!\n");
	return false;
	}
	return frame->SetBufferLength(mkv_len);
	}

	bool Webm2Pes::WritePesPacket(const VideoFrame& frame,
	PacketDataBuffer* packet_data) {
	if (frame.buffer().data.get() == nullptr \|\| frame.buffer().length < 1)
	return false;

	Ranges frame_ranges;
	if (frame.codec() == VideoFrame::kVP9) {
	bool error = false;
	const bool has_superframe_index =
	ParseVP9SuperFrameIndex(frame.buffer().data.get(),
	frame.buffer().length, &frame_ranges, &error);
	if (error) {
	std::fprintf(stderr, "Webm2Pes: Superframe index parse failed.\n");
	return false;
	}
	if (has_superframe_index == false) {
	frame_ranges.push_back(Range(0, frame.buffer().length));
	}
	} else {
	frame_ranges.push_back(Range(0, frame.buffer().length));
	}

	const std::int64_t khz90_pts =
	NanosecondsTo90KhzTicks(frame.nanosecond_pts());
	PesHeader header;
	header.optional_header.SetPtsBits(khz90_pts);

	packet_data->clear();

	for (const Range& packet_payload_range : frame_ranges) {
	std::size_t extra_bytes = 0;
	if (packet_payload_range.length > kMaxPayloadSize) {
	extra_bytes = packet_payload_range.length - kMaxPayloadSize;
	}
	if (packet_payload_range.length + packet_payload_range.offset >
	frame.buffer().length) {
	std::fprintf(stderr, "Webm2Pes: Invalid frame length.\n");
	return false;
	}

	// First packet of new frame. Always include PTS and BCMV header.
	header.packet_length =
	packet_payload_range.length - extra_bytes + BCMVHeader::size();
	if (header.Write(true, packet_data) != true) {
	std::fprintf(stderr, "Webm2Pes: packet header write failed.\n");
	return false;
	}

	BCMVHeader bcmv_header(static_cast<uint32_t>(packet_payload_range.length));
	if (bcmv_header.Write(packet_data) != true) {
	std::fprintf(stderr, "Webm2Pes: BCMV write failed.\n");
	return false;
	}

	// Insert the payload at the end of \|packet_data\|.
	const std::uint8_t* const payload_start =
	frame.buffer().data.get() + packet_payload_range.offset;

	const std::size_t bytes_to_copy = packet_payload_range.length - extra_bytes;
	if (CopyAndEscapeStartCodes(payload_start, bytes_to_copy, packet_data) ==
	false) {
	fprintf(stderr, "Webm2Pes: Payload write failed.\n");
	return false;
	}

	std::size_t bytes_copied = bytes_to_copy;
	while (extra_bytes) {
	// Write PES packets for the remaining data, but omit the PTS and BCMV
	// header.
	const std::size_t extra_bytes_to_copy =
	std::min(kMaxPayloadSize, extra_bytes);
	extra_bytes -= extra_bytes_to_copy;
	header.packet_length = extra_bytes_to_copy;
	if (header.Write(false, packet_data) != true) {
	fprintf(stderr, "Webm2pes: fragment write failed.\n");
	return false;
	}

	const std::uint8_t* fragment_start = payload_start + bytes_copied;
	if (CopyAndEscapeStartCodes(fragment_start, extra_bytes_to_copy,
	packet_data) == false) {
	fprintf(stderr, "Webm2Pes: Payload write failed.\n");
	return false;
	}

	bytes_copied += extra_bytes_to_copy;
	}
	}

	return true;
	}

	bool CopyAndEscapeStartCodes(const std::uint8_t* raw_input,
	std::size_t raw_input_length,
	PacketDataBuffer* packet_buffer) {
	if (raw_input == nullptr \|\| raw_input_length < 1 \|\| packet_buffer == nullptr)
	return false;

	int num_zeros = 0;
	for (std::size_t i = 0; i < raw_input_length; ++i) {
	const uint8_t byte = raw_input[i];

	if (byte == 0) {
	++num_zeros;
	} else if (num_zeros >= 2 && (byte == 0x1 \|\| byte == 0x3)) {
	packet_buffer->push_back(0x3);
	num_zeros = 0;
	} else {
	num_zeros = 0;
	}

	packet_buffer->push_back(byte);
	}

	return true;
	}

	} // namespace libwebm