1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.media; 18 19 import java.nio.ByteBuffer; 20 import java.lang.AutoCloseable; 21 22 import android.graphics.Rect; 23 24 /** 25 * <p>A single complete image buffer to use with a media source such as a 26 * {@link MediaCodec} or a 27 * {@link android.hardware.camera2.CameraDevice CameraDevice}.</p> 28 * 29 * <p>This class allows for efficient direct application access to the pixel 30 * data of the Image through one or more 31 * {@link java.nio.ByteBuffer ByteBuffers}. Each buffer is encapsulated in a 32 * {@link Plane} that describes the layout of the pixel data in that plane. Due 33 * to this direct access, and unlike the {@link android.graphics.Bitmap Bitmap} class, 34 * Images are not directly usable as as UI resources.</p> 35 * 36 * <p>Since Images are often directly produced or consumed by hardware 37 * components, they are a limited resource shared across the system, and should 38 * be closed as soon as they are no longer needed.</p> 39 * 40 * <p>For example, when using the {@link ImageReader} class to read out Images 41 * from various media sources, not closing old Image objects will prevent the 42 * availability of new Images once 43 * {@link ImageReader#getMaxImages the maximum outstanding image count} is 44 * reached. When this happens, the function acquiring new Images will typically 45 * throw an {@link IllegalStateException}.</p> 46 * 47 * @see ImageReader 48 */ 49 public abstract class Image implements AutoCloseable { 50 /** 51 * @hide 52 */ 53 protected boolean mIsImageValid = false; 54 55 /** 56 * @hide 57 */ Image()58 protected Image() { 59 } 60 61 /** 62 * Throw IllegalStateException if the image is invalid (already closed). 63 * 64 * @hide 65 */ throwISEIfImageIsInvalid()66 protected void throwISEIfImageIsInvalid() { 67 if (!mIsImageValid) { 68 throw new IllegalStateException("Image is already closed"); 69 } 70 } 71 /** 72 * Get the format for this image. This format determines the number of 73 * ByteBuffers needed to represent the image, and the general layout of the 74 * pixel data in each in ByteBuffer. 75 * 76 * <p> 77 * The format is one of the values from 78 * {@link android.graphics.ImageFormat ImageFormat}. The mapping between the 79 * formats and the planes is as follows: 80 * </p> 81 * 82 * <table> 83 * <tr> 84 * <th>Format</th> 85 * <th>Plane count</th> 86 * <th>Layout details</th> 87 * </tr> 88 * <tr> 89 * <td>{@link android.graphics.ImageFormat#JPEG JPEG}</td> 90 * <td>1</td> 91 * <td>Compressed data, so row and pixel strides are 0. To uncompress, use 92 * {@link android.graphics.BitmapFactory#decodeByteArray BitmapFactory#decodeByteArray}. 93 * </td> 94 * </tr> 95 * <tr> 96 * <td>{@link android.graphics.ImageFormat#YUV_420_888 YUV_420_888}</td> 97 * <td>3</td> 98 * <td>A luminance plane followed by the Cb and Cr chroma planes. 99 * The chroma planes have half the width and height of the luminance 100 * plane (4:2:0 subsampling). Each pixel sample in each plane has 8 bits. 101 * Each plane has its own row stride and pixel stride.</td> 102 * </tr> 103 * <tr> 104 * <td>{@link android.graphics.ImageFormat#YUV_422_888 YUV_422_888}</td> 105 * <td>3</td> 106 * <td>A luminance plane followed by the Cb and Cr chroma planes. 107 * The chroma planes have half the width and the full height of the luminance 108 * plane (4:2:2 subsampling). Each pixel sample in each plane has 8 bits. 109 * Each plane has its own row stride and pixel stride.</td> 110 * </tr> 111 * <tr> 112 * <td>{@link android.graphics.ImageFormat#YUV_444_888 YUV_444_888}</td> 113 * <td>3</td> 114 * <td>A luminance plane followed by the Cb and Cr chroma planes. 115 * The chroma planes have the same width and height as that of the luminance 116 * plane (4:4:4 subsampling). Each pixel sample in each plane has 8 bits. 117 * Each plane has its own row stride and pixel stride.</td> 118 * </tr> 119 * <tr> 120 * <td>{@link android.graphics.ImageFormat#FLEX_RGB_888 FLEX_RGB_888}</td> 121 * <td>3</td> 122 * <td>A R (red) plane followed by the G (green) and B (blue) planes. 123 * All planes have the same widths and heights. 124 * Each pixel sample in each plane has 8 bits. 125 * Each plane has its own row stride and pixel stride.</td> 126 * </tr> 127 * <tr> 128 * <td>{@link android.graphics.ImageFormat#FLEX_RGBA_8888 FLEX_RGBA_8888}</td> 129 * <td>4</td> 130 * <td>A R (red) plane followed by the G (green), B (blue), and 131 * A (alpha) planes. All planes have the same widths and heights. 132 * Each pixel sample in each plane has 8 bits. 133 * Each plane has its own row stride and pixel stride.</td> 134 * </tr> 135 * <tr> 136 * <td>{@link android.graphics.ImageFormat#RAW_SENSOR RAW_SENSOR}</td> 137 * <td>1</td> 138 * <td>A single plane of raw sensor image data, with 16 bits per color 139 * sample. The details of the layout need to be queried from the source of 140 * the raw sensor data, such as 141 * {@link android.hardware.camera2.CameraDevice CameraDevice}. 142 * </td> 143 * </tr> 144 * </table> 145 * 146 * @see android.graphics.ImageFormat 147 */ getFormat()148 public abstract int getFormat(); 149 150 /** 151 * The width of the image in pixels. For formats where some color channels 152 * are subsampled, this is the width of the largest-resolution plane. 153 */ getWidth()154 public abstract int getWidth(); 155 156 /** 157 * The height of the image in pixels. For formats where some color channels 158 * are subsampled, this is the height of the largest-resolution plane. 159 */ getHeight()160 public abstract int getHeight(); 161 162 /** 163 * Get the timestamp associated with this frame. 164 * <p> 165 * The timestamp is measured in nanoseconds, and is normally monotonically 166 * increasing. The timestamps for the images from different sources may have 167 * different timebases therefore may not be comparable. The specific meaning and 168 * timebase of the timestamp depend on the source providing images. See 169 * {@link android.hardware.Camera Camera}, 170 * {@link android.hardware.camera2.CameraDevice CameraDevice}, 171 * {@link MediaPlayer} and {@link MediaCodec} for more details. 172 * </p> 173 */ getTimestamp()174 public abstract long getTimestamp(); 175 176 /** 177 * Set the timestamp associated with this frame. 178 * <p> 179 * The timestamp is measured in nanoseconds, and is normally monotonically 180 * increasing. The timestamps for the images from different sources may have 181 * different timebases therefore may not be comparable. The specific meaning and 182 * timebase of the timestamp depend on the source providing images. See 183 * {@link android.hardware.Camera Camera}, 184 * {@link android.hardware.camera2.CameraDevice CameraDevice}, 185 * {@link MediaPlayer} and {@link MediaCodec} for more details. 186 * </p> 187 * <p> 188 * For images dequeued from {@link ImageWriter} via 189 * {@link ImageWriter#dequeueInputImage()}, it's up to the application to 190 * set the timestamps correctly before sending them back to the 191 * {@link ImageWriter}, or the timestamp will be generated automatically when 192 * {@link ImageWriter#queueInputImage queueInputImage()} is called. 193 * </p> 194 * 195 * @param timestamp The timestamp to be set for this image. 196 */ setTimestamp(long timestamp)197 public void setTimestamp(long timestamp) { 198 throwISEIfImageIsInvalid(); 199 return; 200 } 201 202 private Rect mCropRect; 203 204 /** 205 * Get the crop rectangle associated with this frame. 206 * <p> 207 * The crop rectangle specifies the region of valid pixels in the image, 208 * using coordinates in the largest-resolution plane. 209 */ getCropRect()210 public Rect getCropRect() { 211 throwISEIfImageIsInvalid(); 212 213 if (mCropRect == null) { 214 return new Rect(0, 0, getWidth(), getHeight()); 215 } else { 216 return new Rect(mCropRect); // return a copy 217 } 218 } 219 220 /** 221 * Set the crop rectangle associated with this frame. 222 * <p> 223 * The crop rectangle specifies the region of valid pixels in the image, 224 * using coordinates in the largest-resolution plane. 225 */ setCropRect(Rect cropRect)226 public void setCropRect(Rect cropRect) { 227 throwISEIfImageIsInvalid(); 228 229 if (cropRect != null) { 230 cropRect = new Rect(cropRect); // make a copy 231 if (!cropRect.intersect(0, 0, getWidth(), getHeight())) { 232 cropRect.setEmpty(); 233 } 234 } 235 mCropRect = cropRect; 236 } 237 238 /** 239 * Get the array of pixel planes for this Image. The number of planes is 240 * determined by the format of the Image. The application will get an empty 241 * array if the image format is {@link android.graphics.ImageFormat#PRIVATE 242 * PRIVATE}, because the image pixel data is not directly accessible. The 243 * application can check the image format by calling 244 * {@link Image#getFormat()}. 245 */ getPlanes()246 public abstract Plane[] getPlanes(); 247 248 /** 249 * Free up this frame for reuse. 250 * <p> 251 * After calling this method, calling any methods on this {@code Image} will 252 * result in an {@link IllegalStateException}, and attempting to read from 253 * or write to {@link ByteBuffer ByteBuffers} returned by an earlier 254 * {@link Plane#getBuffer} call will have undefined behavior. If the image 255 * was obtained from {@link ImageWriter} via 256 * {@link ImageWriter#dequeueInputImage()}, after calling this method, any 257 * image data filled by the application will be lost and the image will be 258 * returned to {@link ImageWriter} for reuse. Images given to 259 * {@link ImageWriter#queueInputImage queueInputImage()} are automatically 260 * closed. 261 * </p> 262 */ 263 @Override close()264 public abstract void close(); 265 266 /** 267 * <p> 268 * Check if the image can be attached to a new owner (e.g. {@link ImageWriter}). 269 * </p> 270 * <p> 271 * This is a package private method that is only used internally. 272 * </p> 273 * 274 * @return true if the image is attachable to a new owner, false if the image is still attached 275 * to its current owner, or the image is a stand-alone image and is not attachable to 276 * a new owner. 277 */ isAttachable()278 boolean isAttachable() { 279 throwISEIfImageIsInvalid(); 280 281 return false; 282 } 283 284 /** 285 * <p> 286 * Get the owner of the {@link Image}. 287 * </p> 288 * <p> 289 * The owner of an {@link Image} could be {@link ImageReader}, {@link ImageWriter}, 290 * {@link MediaCodec} etc. This method returns the owner that produces this image, or null 291 * if the image is stand-alone image or the owner is unknown. 292 * </p> 293 * <p> 294 * This is a package private method that is only used internally. 295 * </p> 296 * 297 * @return The owner of the Image. 298 */ getOwner()299 Object getOwner() { 300 throwISEIfImageIsInvalid(); 301 302 return null; 303 } 304 305 /** 306 * Get native context (buffer pointer) associated with this image. 307 * <p> 308 * This is a package private method that is only used internally. It can be 309 * used to get the native buffer pointer and passed to native, which may be 310 * passed to {@link ImageWriter#attachAndQueueInputImage} to avoid a reverse 311 * JNI call. 312 * </p> 313 * 314 * @return native context associated with this Image. 315 */ getNativeContext()316 long getNativeContext() { 317 throwISEIfImageIsInvalid(); 318 319 return 0; 320 } 321 322 /** 323 * <p>A single color plane of image data.</p> 324 * 325 * <p>The number and meaning of the planes in an Image are determined by the 326 * format of the Image.</p> 327 * 328 * <p>Once the Image has been closed, any access to the the plane's 329 * ByteBuffer will fail.</p> 330 * 331 * @see #getFormat 332 */ 333 public static abstract class Plane { 334 /** 335 * @hide 336 */ Plane()337 protected Plane() { 338 } 339 340 /** 341 * <p>The row stride for this color plane, in bytes.</p> 342 * 343 * <p>This is the distance between the start of two consecutive rows of 344 * pixels in the image. The row stride is always greater than 0.</p> 345 */ getRowStride()346 public abstract int getRowStride(); 347 /** 348 * <p>The distance between adjacent pixel samples, in bytes.</p> 349 * 350 * <p>This is the distance between two consecutive pixel values in a row 351 * of pixels. It may be larger than the size of a single pixel to 352 * account for interleaved image data or padded formats. 353 * The pixel stride is always greater than 0.</p> 354 */ getPixelStride()355 public abstract int getPixelStride(); 356 /** 357 * <p>Get a direct {@link java.nio.ByteBuffer ByteBuffer} 358 * containing the frame data.</p> 359 * 360 * <p>In particular, the buffer returned will always have 361 * {@link java.nio.ByteBuffer#isDirect isDirect} return {@code true}, so 362 * the underlying data could be mapped as a pointer in JNI without doing 363 * any copies with {@code GetDirectBufferAddress}.</p> 364 * 365 * <p>For raw formats, each plane is only guaranteed to contain data 366 * up to the last pixel in the last row. In other words, the stride 367 * after the last row may not be mapped into the buffer. This is a 368 * necessary requirement for any interleaved format.</p> 369 * 370 * @return the byte buffer containing the image data for this plane. 371 */ getBuffer()372 public abstract ByteBuffer getBuffer(); 373 } 374 375 } 376