// 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_FFMPEG_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_
#define MEDIA_FILTERS_FFMPEG_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_
#include "base/basictypes.h"
#include "media/filters/h264_to_annex_b_bitstream_converter.h"
// Forward declarations for FFmpeg datatypes used.
struct AVCodecContext;
struct AVPacket;
namespace media {
// Bitstream converter that converts H.264 bitstream based FFmpeg packets into
// H.264 Annex B bytestream format.
class MEDIA_EXPORT FFmpegH264ToAnnexBBitstreamConverter {
public:
// The |stream_context| will be used during conversion and should be the
// AVCodecContext for the stream sourcing these packets. A reference to
// |stream_context| is retained, so it must outlive this class.
explicit FFmpegH264ToAnnexBBitstreamConverter(AVCodecContext* stream_context);
~FFmpegH264ToAnnexBBitstreamConverter();
// Converts |packet| to H.264 Annex B bytestream format. This conversion is
// on single NAL unit basis which is contained within the |packet| with the
// exception of the first packet which is prepended with the AVC decoder
// configuration record information. For example:
//
// NAL unit #1 ==> bytestream buffer #1 (AVC configuraion + NAL unit #1)
// NAL unit #2 ==> bytestream buffer #2 (NAL unit #2)
// ...
// NAL unit #n ==> bytestream buffer #n (NAL unit #n)
//
// Returns true if conversion succeeded. In this case, the output will be
// stored into the |packet|. But user should be aware that this conversion can
// free and reallocate the |packet|, if it needs to do so to fit it in.
// FFmpeg allocation methods will be used for buffer allocation to ensure
// compatibility with FFmpeg's memory management.
//
// Returns false if conversion failed. In this case, the |packet| will not
// be changed.
bool ConvertPacket(AVPacket* packet);
private:
// Actual converter class.
H264ToAnnexBBitstreamConverter converter_;
// Flag for indicating whether global parameter sets have been processed.
bool configuration_processed_;
// Variable to hold a pointer to memory where we can access the global
// data from the FFmpeg file format's global headers.
AVCodecContext* stream_context_;
DISALLOW_COPY_AND_ASSIGN(FFmpegH264ToAnnexBBitstreamConverter);
};
} // namespace media
#endif // MEDIA_FILTERS_FFMPEG_H264_TO_ANNEX_B_BITSTREAM_CONVERTER_H_