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_
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
19struct jpeg_common_struct;
20struct jpeg_decompress_struct;
21struct jpeg_source_mgr;
22
23namespace libyuv {
24
25#ifdef __cplusplus
26extern "C" {
27#endif
28
29LIBYUV_BOOL ValidateJpeg(const uint8* sample, size_t sample_size);
30
31#ifdef __cplusplus
32}  // extern "C"
33#endif
34
35static const uint32 kUnknownDataSize = 0xFFFFFFFF;
36
37enum JpegSubsamplingType {
38  kJpegYuv420,
39  kJpegYuv422,
40  kJpegYuv444,
41  kJpegYuv400,
42  kJpegUnknown
43};
44
45struct Buffer {
46  const uint8* data;
47  int len;
48};
49
50struct BufferVector {
51  Buffer* buffers;
52  int len;
53  int pos;
54};
55
56struct SetJmpErrorMgr;
57
58// MJPEG ("Motion JPEG") is a pseudo-standard video codec where the frames are
59// simply independent JPEG images with a fixed huffman table (which is omitted).
60// It is rarely used in video transmission, but is common as a camera capture
61// format, especially in Logitech devices. This class implements a decoder for
62// MJPEG frames.
63//
64// See http://tools.ietf.org/html/rfc2435
65class LIBYUV_API MJpegDecoder {
66 public:
67  typedef void (*CallbackFunction)(void* opaque,
68                                   const uint8* const* data,
69                                   const int* strides,
70                                   int rows);
71
72  static const int kColorSpaceUnknown;
73  static const int kColorSpaceGrayscale;
74  static const int kColorSpaceRgb;
75  static const int kColorSpaceYCbCr;
76  static const int kColorSpaceCMYK;
77  static const int kColorSpaceYCCK;
78
79  MJpegDecoder();
80  ~MJpegDecoder();
81
82  // Loads a new frame, reads its headers, and determines the uncompressed
83  // image format.
84  // Returns LIBYUV_TRUE if image looks valid and format is supported.
85  // If return value is LIBYUV_TRUE, then the values for all the following
86  // getters are populated.
87  // src_len is the size of the compressed mjpeg frame in bytes.
88  LIBYUV_BOOL LoadFrame(const uint8* src, size_t src_len);
89
90  // Returns width of the last loaded frame in pixels.
91  int GetWidth();
92
93  // Returns height of the last loaded frame in pixels.
94  int GetHeight();
95
96  // Returns format of the last loaded frame. The return value is one of the
97  // kColorSpace* constants.
98  int GetColorSpace();
99
100  // Number of color components in the color space.
101  int GetNumComponents();
102
103  // Sample factors of the n-th component.
104  int GetHorizSampFactor(int component);
105
106  int GetVertSampFactor(int component);
107
108  int GetHorizSubSampFactor(int component);
109
110  int GetVertSubSampFactor(int component);
111
112  // Public for testability.
113  int GetImageScanlinesPerImcuRow();
114
115  // Public for testability.
116  int GetComponentScanlinesPerImcuRow(int component);
117
118  // Width of a component in bytes.
119  int GetComponentWidth(int component);
120
121  // Height of a component.
122  int GetComponentHeight(int component);
123
124  // Width of a component in bytes with padding for DCTSIZE. Public for testing.
125  int GetComponentStride(int component);
126
127  // Size of a component in bytes.
128  int GetComponentSize(int component);
129
130  // Call this after LoadFrame() if you decide you don't want to decode it
131  // after all.
132  LIBYUV_BOOL UnloadFrame();
133
134  // Decodes the entire image into a one-buffer-per-color-component format.
135  // dst_width must match exactly. dst_height must be <= to image height; if
136  // less, the image is cropped. "planes" must have size equal to at least
137  // GetNumComponents() and they must point to non-overlapping buffers of size
138  // at least GetComponentSize(i). The pointers in planes are incremented
139  // to point to after the end of the written data.
140  // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded.
141  LIBYUV_BOOL DecodeToBuffers(uint8** planes, int dst_width, int dst_height);
142
143  // Decodes the entire image and passes the data via repeated calls to a
144  // callback function. Each call will get the data for a whole number of
145  // image scanlines.
146  // TODO(fbarchard): Add dst_x, dst_y to allow specific rect to be decoded.
147  LIBYUV_BOOL DecodeToCallback(CallbackFunction fn,
148                               void* opaque,
149                               int dst_width,
150                               int dst_height);
151
152  // The helper function which recognizes the jpeg sub-sampling type.
153  static JpegSubsamplingType JpegSubsamplingTypeHelper(
154      int* subsample_x,
155      int* subsample_y,
156      int number_of_components);
157
158 private:
159  void AllocOutputBuffers(int num_outbufs);
160  void DestroyOutputBuffers();
161
162  LIBYUV_BOOL StartDecode();
163  LIBYUV_BOOL FinishDecode();
164
165  void SetScanlinePointers(uint8** data);
166  LIBYUV_BOOL DecodeImcuRow();
167
168  int GetComponentScanlinePadding(int component);
169
170  // A buffer holding the input data for a frame.
171  Buffer buf_;
172  BufferVector buf_vec_;
173
174  jpeg_decompress_struct* decompress_struct_;
175  jpeg_source_mgr* source_mgr_;
176  SetJmpErrorMgr* error_mgr_;
177
178  // LIBYUV_TRUE iff at least one component has scanline padding. (i.e.,
179  // GetComponentScanlinePadding() != 0.)
180  LIBYUV_BOOL has_scanline_padding_;
181
182  // Temporaries used to point to scanline outputs.
183  int num_outbufs_;  // Outermost size of all arrays below.
184  uint8*** scanlines_;
185  int* scanlines_sizes_;
186  // Temporary buffer used for decoding when we can't decode directly to the
187  // output buffers. Large enough for just one iMCU row.
188  uint8** databuf_;
189  int* databuf_strides_;
190};
191
192}  // namespace libyuv
193
194#endif  //  __cplusplus
195#endif  // INCLUDE_LIBYUV_MJPEG_DECODER_H_
196