dom/media/webm/EbmlComposer.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   4  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef EbmlComposer_h_
   7 #define EbmlComposer_h_
   8 #include "nsTArray.h"
   9 #include "ContainerWriter.h"
  10
  11 namespace mozilla {
  12
  13 /*
  14  * A WebM muxer helper for package the valid WebM format.
  15  */
  16 class EbmlComposer {
  17  public:
  18   EbmlComposer() = default;
  19   /*
  20    * Assign the parameters which header requires. These can be called multiple
  21    * times to change paramter values until GenerateHeader() is called, when this
  22    * becomes illegal to call again.
  23    */
  24   void SetVideoConfig(uint32_t aWidth, uint32_t aHeight, uint32_t aDisplayWidth,
  25                       uint32_t aDisplayHeight);
  26   void SetAudioConfig(uint32_t aSampleFreq, uint32_t aChannels);
  27   /*
  28    * Set the CodecPrivateData for writing in header.
  29    */
  30   void SetAudioCodecPrivateData(nsTArray<uint8_t>& aBufs) {
  31     mCodecPrivateData.AppendElements(aBufs);
  32   }
  33   /*
  34    * Generate the whole WebM header with the configured tracks, and make
  35    * available to ExtractBuffer. Must only be called once.
  36    */
  37   void GenerateHeader();
  38   /*
  39    * Insert media encoded buffer into muxer and it would be package
  40    * into SimpleBlock. If no cluster is opened, new cluster will start for
  41    * writing. Frames passed to this function should already have any codec delay
  42    * applied.
  43    */
  44   nsresult WriteSimpleBlock(EncodedFrame* aFrame);
  45   /*
  46    * Get valid cluster data.
  47    */
  48   void ExtractBuffer(nsTArray<nsTArray<uint8_t>>* aDestBufs,
  49                      uint32_t aFlag = 0);
  50
  51  private:
  52   // True once we have written the first cluster header. We cannot serialize any
  53   // P-frames until this is true, since we start a new cluster every I-frame.
  54   bool mHasWrittenCluster = false;
  55   // The timecode of the cluster.
  56   uint64_t mCurrentClusterTimecode = 0;
  57
  58   // Written data to be flushed out by ExtractBuffer().
  59   nsTArray<nsTArray<uint8_t>> mBuffer;
  60
  61   // True when Metadata has been serialized into mBuffer.
  62   bool mMetadataFinished = false;
  63
  64   // Video configuration
  65   int mWidth = 0;
  66   int mHeight = 0;
  67   int mDisplayWidth = 0;
  68   int mDisplayHeight = 0;
  69   bool mHasVideo = false;
  70
  71   // Audio configuration
  72   float mSampleFreq = 0;
  73   int mChannels = 0;
  74   bool mHasAudio = false;
  75   // Audio codec specific header data.
  76   nsTArray<uint8_t> mCodecPrivateData;
  77 };
  78
  79 }  // namespace mozilla
  80
  81 #endif