The Tor Browser: content/media/webm/EbmlComposer.cpp@44a2da4a2ab2 (annotated)

content/media/webm/EbmlComposer.cpp@44a2da4a2ab2 (annotated)

content/media/webm/EbmlComposer.cpp

Fri, 16 Jan 2015 04:50:19 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 04:50:19 +0100
branch: TOR_BUG_9701
changeset 13: 44a2da4a2ab2
permissions: -rw-r--r--

Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "EbmlComposer.h"
 #include "libmkv/EbmlIDs.h"
 #include "libmkv/EbmlWriter.h"
 #include "libmkv/WebMElement.h"
 #include "prtime.h"
 namespace mozilla {
 // Timecode scale in nanoseconds
 static const unsigned long TIME_CODE_SCALE = 1000000;
 // The WebM header size without audio CodecPrivateData
 static const int32_t DEFAULT_HEADER_SIZE = 1024;
 void EbmlComposer::GenerateHeader()
 {
   // Write the EBML header.
   EbmlGlobal ebml;
   // The WEbM header default size usually smaller than 1k.
   nsAutoArrayPtr<uint8_t> buffer(new uint8_t[DEFAULT_HEADER_SIZE +
                                              mCodecPrivateData.Length()]);
   ebml.buf = buffer.get();
   ebml.offset = 0;
   writeHeader(&ebml);
   {
     EbmlLoc segEbmlLoc, ebmlLocseg, ebmlLoc;
     Ebml_StartSubElement(&ebml, &segEbmlLoc, Segment);
     {
       Ebml_StartSubElement(&ebml, &ebmlLocseg, SeekHead);
       // Todo: We don't know the exact sizes of encoded data and
       // ignore this section.
       Ebml_EndSubElement(&ebml, &ebmlLocseg);
       writeSegmentInformation(&ebml, &ebmlLoc, TIME_CODE_SCALE, 0);
       {
         EbmlLoc trackLoc;
         Ebml_StartSubElement(&ebml, &trackLoc, Tracks);
         {
           // Video
           if (mWidth > 0 && mHeight > 0) {
             writeVideoTrack(&ebml, 0x1, 0, "V_VP8",
                             mWidth, mHeight,
                             mDisplayWidth, mDisplayHeight, mFrameRate);
           }
           // Audio
           if (mCodecPrivateData.Length() > 0) {
             writeAudioTrack(&ebml, 0x2, 0x0, "A_VORBIS", mSampleFreq,
                             mChannels, mCodecPrivateData.Elements(),
                             mCodecPrivateData.Length());
           }
         }
         Ebml_EndSubElement(&ebml, &trackLoc);
       }
     }
     // The Recording length is unknown and
     // ignore write the whole Segment element size
   }
   MOZ_ASSERT(ebml.offset <= DEFAULT_HEADER_SIZE + mCodecPrivateData.Length(),
              "write more data > EBML_BUFFER_SIZE");
   auto block = mClusterBuffs.AppendElement();
   block->SetLength(ebml.offset);
   memcpy(block->Elements(), ebml.buf, ebml.offset);
   mFlushState |= FLUSH_METADATA;
 }
 void EbmlComposer::FinishMetadata()
 {
   if (mFlushState & FLUSH_METADATA) {
     // We don't remove the first element of mClusterBuffs because the
     // |mClusterHeaderIndex| may have value.
     mClusterCanFlushBuffs.AppendElement()->SwapElements(mClusterBuffs[0]);
     mFlushState &= ~FLUSH_METADATA;
   }
 }
 void EbmlComposer::FinishCluster()
 {
   FinishMetadata();
   if (!(mFlushState & FLUSH_CLUSTER)) {
     // No completed cluster available.
     return;
   }
   MOZ_ASSERT(mClusterLengthLoc > 0);
   EbmlGlobal ebml;
   EbmlLoc ebmlLoc;
   ebmlLoc.offset = mClusterLengthLoc;
   ebml.offset = mClusterBuffs[mClusterHeaderIndex].Length();
   ebml.buf = mClusterBuffs[mClusterHeaderIndex].Elements();
   Ebml_EndSubElement(&ebml, &ebmlLoc);
   // Move the mClusterBuffs data from mClusterHeaderIndex that we can skip
   // the metadata and the rest P-frames after ContainerWriter::FLUSH_NEEDED.
   for (uint32_t i = mClusterHeaderIndex; i < mClusterBuffs.Length(); i++) {
     mClusterCanFlushBuffs.AppendElement()->SwapElements(mClusterBuffs[i]);
   }
   mClusterHeaderIndex = 0;
   mClusterLengthLoc = 0;
   mClusterBuffs.Clear();
   mFlushState &= ~FLUSH_CLUSTER;
 }
 void
 EbmlComposer::WriteSimpleBlock(EncodedFrame* aFrame)
 {
   EbmlGlobal ebml;
   ebml.offset = 0;
   if (aFrame->GetFrameType() == EncodedFrame::FrameType::VP8_I_FRAME) {
     FinishCluster();
   }
   auto block = mClusterBuffs.AppendElement();
   block->SetLength(aFrame->GetFrameData().Length() + DEFAULT_HEADER_SIZE);
   ebml.buf = block->Elements();
   if (aFrame->GetFrameType() == EncodedFrame::FrameType::VP8_I_FRAME) {
     EbmlLoc ebmlLoc;
     Ebml_StartSubElement(&ebml, &ebmlLoc, Cluster);
     MOZ_ASSERT(mClusterBuffs.Length() > 0);
     // current cluster header array index
     mClusterHeaderIndex = mClusterBuffs.Length() - 1;
     mClusterLengthLoc = ebmlLoc.offset;
     mClusterTimecode = aFrame->GetTimeStamp() / PR_USEC_PER_MSEC;
     Ebml_SerializeUnsigned(&ebml, Timecode, mClusterTimecode);
     mFlushState |= FLUSH_CLUSTER;
   }
   if (aFrame->GetFrameType() != EncodedFrame::FrameType::VORBIS_AUDIO_FRAME) {
     short timeCode = aFrame->GetTimeStamp() / PR_USEC_PER_MSEC
                      - mClusterTimecode;
     writeSimpleBlock(&ebml, 0x1, timeCode, aFrame->GetFrameType() ==
                      EncodedFrame::FrameType::VP8_I_FRAME,
 , 0, (unsigned char*)aFrame->GetFrameData().Elements(),
                      aFrame->GetFrameData().Length());
   } else {
     writeSimpleBlock(&ebml, 0x2, 0, false,
 , 0, (unsigned char*)aFrame->GetFrameData().Elements(),
                      aFrame->GetFrameData().Length());
   }
   MOZ_ASSERT(ebml.offset <= DEFAULT_HEADER_SIZE +
              aFrame->GetFrameData().Length(),
              "write more data > EBML_BUFFER_SIZE");
   block->SetLength(ebml.offset);
 }
 void
 EbmlComposer::SetVideoConfig(uint32_t aWidth, uint32_t aHeight,
                              uint32_t aDisplayWidth, uint32_t aDisplayHeight,
                              float aFrameRate)
 {
   MOZ_ASSERT(aWidth > 0, "Width should > 0");
   MOZ_ASSERT(aHeight > 0, "Height should > 0");
   MOZ_ASSERT(aDisplayWidth > 0, "DisplayWidth should > 0");
   MOZ_ASSERT(aDisplayHeight > 0, "DisplayHeight should > 0");
   MOZ_ASSERT(aFrameRate > 0, "FrameRate should > 0");
   mWidth = aWidth;
   mHeight = aHeight;
   mDisplayWidth = aDisplayWidth;
   mDisplayHeight = aDisplayHeight;
   mFrameRate = aFrameRate;
 }
 void
 EbmlComposer::SetAudioConfig(uint32_t aSampleFreq, uint32_t aChannels,
                              uint32_t aBitDepth)
 {
   MOZ_ASSERT(aSampleFreq > 0, "SampleFreq should > 0");
   MOZ_ASSERT(aBitDepth > 0, "BitDepth should > 0");
   MOZ_ASSERT(aChannels > 0, "Channels should > 0");
   mSampleFreq = aSampleFreq;
   mBitDepth = aBitDepth;
   mChannels = aChannels;
 }
 void
 EbmlComposer::ExtractBuffer(nsTArray<nsTArray<uint8_t> >* aDestBufs,
                             uint32_t aFlag)
 {
   if ((aFlag & ContainerWriter::FLUSH_NEEDED) ||
       (aFlag & ContainerWriter::GET_HEADER))
   {
     FinishMetadata();
   }
   if (aFlag & ContainerWriter::FLUSH_NEEDED)
   {
     FinishCluster();
   }
   // aDestBufs may have some element
   for (uint32_t i = 0; i < mClusterCanFlushBuffs.Length(); i++) {
     aDestBufs->AppendElement()->SwapElements(mClusterCanFlushBuffs[i]);
   }
   mClusterCanFlushBuffs.Clear();
 }
 EbmlComposer::EbmlComposer()
   : mFlushState(FLUSH_NONE)
   , mClusterHeaderIndex(0)
   , mClusterLengthLoc(0)
   , mClusterTimecode(0)
   , mWidth(0)
   , mHeight(0)
   , mFrameRate(0)
   , mSampleFreq(0)
   , mBitDepth(0)
   , mChannels(0)
 {}
 }

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content/media/webm/EbmlComposer.cpp@44a2da4a2ab2 (annotated)

content/media/webm/EbmlComposer.cpp