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Diffstat (limited to 'thirdparties/common/include/libyuv/libyuv/mjpeg_decoder.h')
-rw-r--r-- | thirdparties/common/include/libyuv/libyuv/mjpeg_decoder.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/thirdparties/common/include/libyuv/libyuv/mjpeg_decoder.h b/thirdparties/common/include/libyuv/libyuv/mjpeg_decoder.h new file mode 100644 index 0000000..c8576e9 --- /dev/null +++ b/thirdparties/common/include/libyuv/libyuv/mjpeg_decoder.h @@ -0,0 +1,186 @@ +/* + * Copyright 2012 The LibYuv 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. + */ + +#ifndef INCLUDE_LIBYUV_MJPEG_DECODER_H_ // NOLINT +#define INCLUDE_LIBYUV_MJPEG_DECODER_H_ + +#include "libyuv/basic_types.h" + +struct jpeg_common_struct; +struct jpeg_decompress_struct; +struct jpeg_source_mgr; + +namespace libyuv { + +static const uint32 kUnknownDataSize = 0xFFFFFFFF; + +enum JpegSubsamplingType { + kJpegYuv420, + kJpegYuv422, + kJpegYuv411, + kJpegYuv444, + kJpegYuv400, + kJpegUnknown +}; + +struct SetJmpErrorMgr; + +// MJPEG ("Motion JPEG") is a pseudo-standard video codec where the frames are +// simply independent JPEG images with a fixed huffman table (which is omitted). +// It is rarely used in video transmission, but is common as a camera capture +// format, especially in Logitech devices. This class implements a decoder for +// MJPEG frames. +// +// See http://tools.ietf.org/html/rfc2435 +class MJpegDecoder { + public: + typedef void (*CallbackFunction)(void* opaque, + const uint8* const* data, + const int* strides, + int rows); + + static const int kColorSpaceUnknown; + static const int kColorSpaceGrayscale; + static const int kColorSpaceRgb; + static const int kColorSpaceYCbCr; + static const int kColorSpaceCMYK; + static const int kColorSpaceYCCK; + + MJpegDecoder(); + ~MJpegDecoder(); + + // Loads a new frame, reads its headers, and determines the uncompressed + // image format. Returns true if image looks valid and format is supported. + // If return value is true, then the values for all the following getters + // are populated. + // src_len is the size of the compressed mjpeg frame in bytes. + bool LoadFrame(const uint8* src, size_t src_len); + + // Returns width of the last loaded frame in pixels. + int GetWidth(); + + // Returns height of the last loaded frame in pixels. + int GetHeight(); + + // Returns format of the last loaded frame. The return value is one of the + // kColorSpace* constants. + int GetColorSpace(); + + // Number of color components in the color space. + int GetNumComponents(); + + // Sample factors of the n-th component. + int GetHorizSampFactor(int component); + + int GetVertSampFactor(int component); + + int GetHorizSubSampFactor(int component); + + int GetVertSubSampFactor(int component); + + // Public for testability + int GetImageScanlinesPerImcuRow(); + + // Public for testability + int GetComponentScanlinesPerImcuRow(int component); + + // Width of a component in bytes. + int GetComponentWidth(int component); + + // Height of a component. + int GetComponentHeight(int component); + + // Width of a component in bytes with padding for DCTSIZE. Public for testing. + int GetComponentStride(int component); + + // Size of a component in bytes. + int GetComponentSize(int component); + + // Call this after LoadFrame() if you decide you don't want to decode it + // after all. + bool UnloadFrame(); + + // Decodes the entire image into a one-buffer-per-color-component format. + // dst_width must match exactly. dst_height must be <= to image height; if + // less, the image is cropped. "planes" must have size equal to at least + // GetNumComponents() and they must point to non-overlapping buffers of size + // at least GetComponentSize(i). The pointers in planes are incremented + // to point to after the end of the written data. + // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded. + bool DecodeToBuffers(uint8** planes, int dst_width, int dst_height); + + // Decodes the entire image and passes the data via repeated calls to a + // callback function. Each call will get the data for a whole number of + // image scanlines. + // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded. + bool DecodeToCallback(CallbackFunction fn, void* opaque, + int dst_width, int dst_height); + + // The helper function which recognizes the jpeg sub-sampling type. + static JpegSubsamplingType JpegSubsamplingTypeHelper( + int* subsample_x, int* subsample_y, int number_of_components); + + private: + struct Buffer { + const uint8* data; + int len; + }; + + struct BufferVector { + Buffer* buffers; + int len; + int pos; + }; + + // Methods that are passed to jpeglib. + static int fill_input_buffer(jpeg_decompress_struct* cinfo); + static void init_source(jpeg_decompress_struct* cinfo); + static void skip_input_data(jpeg_decompress_struct* cinfo, + long num_bytes); // NOLINT + static void term_source(jpeg_decompress_struct* cinfo); + + static void ErrorHandler(jpeg_common_struct* cinfo); + + void AllocOutputBuffers(int num_outbufs); + void DestroyOutputBuffers(); + + bool StartDecode(); + bool FinishDecode(); + + void SetScanlinePointers(uint8** data); + bool DecodeImcuRow(); + + int GetComponentScanlinePadding(int component); + + // A buffer holding the input data for a frame. + Buffer buf_; + BufferVector buf_vec_; + + jpeg_decompress_struct* decompress_struct_; + jpeg_source_mgr* source_mgr_; + SetJmpErrorMgr* error_mgr_; + + // true iff at least one component has scanline padding. (i.e., + // GetComponentScanlinePadding() != 0.) + bool has_scanline_padding_; + + // Temporaries used to point to scanline outputs. + int num_outbufs_; // Outermost size of all arrays below. + uint8*** scanlines_; + int* scanlines_sizes_; + // Temporary buffer used for decoding when we can't decode directly to the + // output buffers. Large enough for just one iMCU row. + uint8** databuf_; + int* databuf_strides_; +}; + +} // namespace libyuv + +#endif // INCLUDE_LIBYUV_MJPEG_DECODER_H_ NOLINT |