// Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef MEDIA_FILTERS_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_ #define MEDIA_FILTERS_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_ #include "base/basictypes.h" #include "media/base/media_export.h" namespace media { // H264ToAnnexBBitstreamConverter is a class to convert H.264 bitstream from // MP4 format (as specified in ISO/IEC 14496-15) into H.264 bytestream // (as specified in ISO/IEC 14496-10 Annex B). class MEDIA_EXPORT H264ToAnnexBBitstreamConverter { public: H264ToAnnexBBitstreamConverter(); ~H264ToAnnexBBitstreamConverter(); // Parses the global AVCDecoderConfigurationRecord from the file format's // headers. Converter will remember the field length from the configuration // headers after this. // // Parameters // configuration_record // Pointer to buffer containing AVCDecoderConfigurationRecord. // configuration_record_size // Size of the buffer in bytes. // // Returns // Required buffer size for AVCDecoderConfigurationRecord when converted // to bytestream format, or 0 if could not determine the configuration // from the input buffer. uint32 ParseConfigurationAndCalculateSize(const uint8* configuration_record, uint32 configuration_record_size); // Calculates needed buffer size for the bitstream converted into bytestream. // Lightweight implementation that does not do the actual conversion. // // Parameters // configuration_record // Pointer to buffer containing AVCDecoderConfigurationRecord. // configuration_record_size // Size of the buffer in bytes. // // Returns // Required buffer size for the input NAL unit buffer when converted // to bytestream format, or 0 if could not determine the configuration // from the input buffer. uint32 CalculateNeededOutputBufferSize(const uint8* input, uint32 input_size) const; // ConvertAVCDecoderConfigToByteStream converts the // AVCDecoderConfigurationRecord from the MP4 headers to bytestream format. // Client is responsible for making sure the output buffer is large enough // to hold the output data. Client can precalculate the needed output buffer // size by using ParseConfigurationAndCalculateSize. // // In case of failed conversion object H264BitstreamConverter may have written // some bytes to buffer pointed by pinput but user should ignore those bytes. // None of the outputs should be considered valid. // // Parameters // pinput // Pointer to buffer containing AVCDecoderConfigurationRecord. // input_size // Size of the buffer in bytes. // poutput // Pointer to buffer where the output should be written to. // poutput_size (i/o) // Pointer to the size of the output buffer. Will contain the number of // bytes written to output after successful call. // // Returns // true if successful conversion // false if conversion not successful (poutput_size will hold the amount // of converted data) bool ConvertAVCDecoderConfigToByteStream(const uint8* input, uint32 input_size, uint8* output, uint32* output_size); // ConvertNalUnitStreamToByteStream converts the NAL unit from MP4 format // to bytestream format. Client is responsible for making sure the output // buffer is large enough to hold the output data. Client can precalculate the // needed output buffer size by using CalculateNeededOutputBufferSize. // // In case of failed conversion object H264BitstreamConverter may have written // some bytes to buffer pointed by pinput but user should ignore those bytes. // None of the outputs should be considered valid. // // Parameters // pinput // Pointer to buffer containing AVCDecoderConfigurationRecord. // input_size // Size of the buffer in bytes. // poutput // Pointer to buffer where the output should be written to. // poutput_size (i/o) // Pointer to the size of the output buffer. Will contain the number of // bytes written to output after successful call. // // Returns // true if successful conversion // false if conversion not successful (poutput_size will hold the amount // of converted data) bool ConvertNalUnitStreamToByteStream(const uint8* input, uint32 input_size, uint8* output, uint32* output_size); private: // Flag for indicating whether global parameter sets have been processed. bool configuration_processed_; // Flag for indicating whether next NAL unit starts new access unit. bool first_nal_unit_in_access_unit_; // Variable to hold interleaving field's length in bytes. uint8 nal_unit_length_field_width_; DISALLOW_COPY_AND_ASSIGN(H264ToAnnexBBitstreamConverter); }; } // namespace media #endif // MEDIA_FILTERS_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_