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| 1 /* |
| 2 * Copyright 2012 The LibYuv Project Authors. All rights reserved. |
| 3 * |
| 4 * Use of this source code is governed by a BSD-style license |
| 5 * that can be found in the LICENSE file in the root of the source |
| 6 * tree. An additional intellectual property rights grant can be found |
| 7 * in the file PATENTS. All contributing project authors may |
| 8 * be found in the AUTHORS file in the root of the source tree. |
| 9 */ |
| 10 |
| 11 #ifndef INCLUDE_LIBYUV_MJPEG_DECODER_H_ // NOLINT |
| 12 #define INCLUDE_LIBYUV_MJPEG_DECODER_H_ |
| 13 |
| 14 #include "libyuv/basic_types.h" |
| 15 |
| 16 #ifdef __cplusplus |
| 17 // NOTE: For a simplified public API use convert.h MJPGToI420(). |
| 18 |
| 19 struct jpeg_common_struct; |
| 20 struct jpeg_decompress_struct; |
| 21 struct jpeg_source_mgr; |
| 22 |
| 23 namespace libyuv { |
| 24 |
| 25 #ifdef __cplusplus |
| 26 extern "C" { |
| 27 #endif |
| 28 |
| 29 LIBYUV_BOOL ValidateJpeg(const uint8* sample, size_t sample_size); |
| 30 |
| 31 #ifdef __cplusplus |
| 32 } // extern "C" |
| 33 #endif |
| 34 |
| 35 static const uint32 kUnknownDataSize = 0xFFFFFFFF; |
| 36 |
| 37 enum JpegSubsamplingType { |
| 38 kJpegYuv420, |
| 39 kJpegYuv422, |
| 40 kJpegYuv411, |
| 41 kJpegYuv444, |
| 42 kJpegYuv400, |
| 43 kJpegUnknown |
| 44 }; |
| 45 |
| 46 struct Buffer { |
| 47 const uint8* data; |
| 48 int len; |
| 49 }; |
| 50 |
| 51 struct BufferVector { |
| 52 Buffer* buffers; |
| 53 int len; |
| 54 int pos; |
| 55 }; |
| 56 |
| 57 struct SetJmpErrorMgr; |
| 58 |
| 59 // MJPEG ("Motion JPEG") is a pseudo-standard video codec where the frames are |
| 60 // simply independent JPEG images with a fixed huffman table (which is omitted). |
| 61 // It is rarely used in video transmission, but is common as a camera capture |
| 62 // format, especially in Logitech devices. This class implements a decoder for |
| 63 // MJPEG frames. |
| 64 // |
| 65 // See http://tools.ietf.org/html/rfc2435 |
| 66 class LIBYUV_API MJpegDecoder { |
| 67 public: |
| 68 typedef void (*CallbackFunction)(void* opaque, |
| 69 const uint8* const* data, |
| 70 const int* strides, |
| 71 int rows); |
| 72 |
| 73 static const int kColorSpaceUnknown; |
| 74 static const int kColorSpaceGrayscale; |
| 75 static const int kColorSpaceRgb; |
| 76 static const int kColorSpaceYCbCr; |
| 77 static const int kColorSpaceCMYK; |
| 78 static const int kColorSpaceYCCK; |
| 79 |
| 80 MJpegDecoder(); |
| 81 ~MJpegDecoder(); |
| 82 |
| 83 // Loads a new frame, reads its headers, and determines the uncompressed |
| 84 // image format. |
| 85 // Returns LIBYUV_TRUE if image looks valid and format is supported. |
| 86 // If return value is LIBYUV_TRUE, then the values for all the following |
| 87 // getters are populated. |
| 88 // src_len is the size of the compressed mjpeg frame in bytes. |
| 89 LIBYUV_BOOL LoadFrame(const uint8* src, size_t src_len); |
| 90 |
| 91 // Returns width of the last loaded frame in pixels. |
| 92 int GetWidth(); |
| 93 |
| 94 // Returns height of the last loaded frame in pixels. |
| 95 int GetHeight(); |
| 96 |
| 97 // Returns format of the last loaded frame. The return value is one of the |
| 98 // kColorSpace* constants. |
| 99 int GetColorSpace(); |
| 100 |
| 101 // Number of color components in the color space. |
| 102 int GetNumComponents(); |
| 103 |
| 104 // Sample factors of the n-th component. |
| 105 int GetHorizSampFactor(int component); |
| 106 |
| 107 int GetVertSampFactor(int component); |
| 108 |
| 109 int GetHorizSubSampFactor(int component); |
| 110 |
| 111 int GetVertSubSampFactor(int component); |
| 112 |
| 113 // Public for testability. |
| 114 int GetImageScanlinesPerImcuRow(); |
| 115 |
| 116 // Public for testability. |
| 117 int GetComponentScanlinesPerImcuRow(int component); |
| 118 |
| 119 // Width of a component in bytes. |
| 120 int GetComponentWidth(int component); |
| 121 |
| 122 // Height of a component. |
| 123 int GetComponentHeight(int component); |
| 124 |
| 125 // Width of a component in bytes with padding for DCTSIZE. Public for testing. |
| 126 int GetComponentStride(int component); |
| 127 |
| 128 // Size of a component in bytes. |
| 129 int GetComponentSize(int component); |
| 130 |
| 131 // Call this after LoadFrame() if you decide you don't want to decode it |
| 132 // after all. |
| 133 LIBYUV_BOOL UnloadFrame(); |
| 134 |
| 135 // Decodes the entire image into a one-buffer-per-color-component format. |
| 136 // dst_width must match exactly. dst_height must be <= to image height; if |
| 137 // less, the image is cropped. "planes" must have size equal to at least |
| 138 // GetNumComponents() and they must point to non-overlapping buffers of size |
| 139 // at least GetComponentSize(i). The pointers in planes are incremented |
| 140 // to point to after the end of the written data. |
| 141 // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded. |
| 142 LIBYUV_BOOL DecodeToBuffers(uint8** planes, int dst_width, int dst_height); |
| 143 |
| 144 // Decodes the entire image and passes the data via repeated calls to a |
| 145 // callback function. Each call will get the data for a whole number of |
| 146 // image scanlines. |
| 147 // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded. |
| 148 LIBYUV_BOOL DecodeToCallback(CallbackFunction fn, void* opaque, |
| 149 int dst_width, int dst_height); |
| 150 |
| 151 // The helper function which recognizes the jpeg sub-sampling type. |
| 152 static JpegSubsamplingType JpegSubsamplingTypeHelper( |
| 153 int* subsample_x, int* subsample_y, int number_of_components); |
| 154 |
| 155 private: |
| 156 |
| 157 void AllocOutputBuffers(int num_outbufs); |
| 158 void DestroyOutputBuffers(); |
| 159 |
| 160 LIBYUV_BOOL StartDecode(); |
| 161 LIBYUV_BOOL FinishDecode(); |
| 162 |
| 163 void SetScanlinePointers(uint8** data); |
| 164 LIBYUV_BOOL DecodeImcuRow(); |
| 165 |
| 166 int GetComponentScanlinePadding(int component); |
| 167 |
| 168 // A buffer holding the input data for a frame. |
| 169 Buffer buf_; |
| 170 BufferVector buf_vec_; |
| 171 |
| 172 jpeg_decompress_struct* decompress_struct_; |
| 173 jpeg_source_mgr* source_mgr_; |
| 174 SetJmpErrorMgr* error_mgr_; |
| 175 |
| 176 // LIBYUV_TRUE iff at least one component has scanline padding. (i.e., |
| 177 // GetComponentScanlinePadding() != 0.) |
| 178 LIBYUV_BOOL has_scanline_padding_; |
| 179 |
| 180 // Temporaries used to point to scanline outputs. |
| 181 int num_outbufs_; // Outermost size of all arrays below. |
| 182 uint8*** scanlines_; |
| 183 int* scanlines_sizes_; |
| 184 // Temporary buffer used for decoding when we can't decode directly to the |
| 185 // output buffers. Large enough for just one iMCU row. |
| 186 uint8** databuf_; |
| 187 int* databuf_strides_; |
| 188 }; |
| 189 |
| 190 } // namespace libyuv |
| 191 |
| 192 #endif // __cplusplus |
| 193 #endif // INCLUDE_LIBYUV_MJPEG_DECODER_H_ NOLINT |
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