libavutil/frame.h

   1 /*
   2  *
   3  * This file is part of Libav.
   4  *
   5  * Libav is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * Libav is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with Libav; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #ifndef AVUTIL_FRAME_H
  21 #define AVUTIL_FRAME_H
  22
  23 #include <stdint.h>
  24
  25 #include "libavcodec/version.h"
  26
  27 #include "avutil.h"
  28 #include "buffer.h"
  29 #include "rational.h"
  30 #include "samplefmt.h"
  31
  32
  33 /**
  34  * This structure describes decoded (raw) audio or video data.
  35  *
  36  * AVFrame must be allocated using av_frame_alloc(). Not that this only
  37  * allocates the AVFrame itself, the buffers for the data must be managed
  38  * through other means (see below).
  39  * AVFrame must be freed with av_frame_free().
  40  *
  41  * AVFrame is typically allocated once and then reused multiple times to hold
  42  * different data (e.g. a single AVFrame to hold frames received from a
  43  * decoder). In such a case, av_frame_unref() will free any references held by
  44  * the frame and reset it to its original clean state before it
  45  * is reused again.
  46  *
  47  * The data described by an AVFrame is usually reference counted through the
  48  * AVBuffer API. The underlying buffer references are stored in AVFrame.buf /
  49  * AVFrame.extended_buf. An AVFrame is considered to be reference counted if at
  50  * least one reference is set, i.e. if AVFrame.buf[0] != NULL. In such a case,
  51  * every single data plane must be contained in one of the buffers in
  52  * AVFrame.buf or AVFrame.extended_buf.
  53  * There may be a single buffer for all the data, or one separate buffer for
  54  * each plane, or anything in between.
  55  *
  56  * sizeof(AVFrame) is not a part of the public ABI, so new fields may be added
  57  * to the end with a minor bump.
  58  */
  59 typedef struct AVFrame {
  60 #define AV_NUM_DATA_POINTERS 8
  61     /**
  62      * pointer to the picture/channel planes.
  63      * This might be different from the first allocated byte
  64      */
  65     uint8_t *data[AV_NUM_DATA_POINTERS];
  66
  67     /**
  68      * For video, size in bytes of each picture line.
  69      * For audio, size in bytes of each plane.
  70      *
  71      * For audio, only linesize[0] may be set. For planar audio, each channel
  72      * plane must be the same size.
  73      */
  74     int linesize[AV_NUM_DATA_POINTERS];
  75
  76     /**
  77      * pointers to the data planes/channels.
  78      *
  79      * For video, this should simply point to data[].
  80      *
  81      * For planar audio, each channel has a separate data pointer, and
  82      * linesize[0] contains the size of each channel buffer.
  83      * For packed audio, there is just one data pointer, and linesize[0]
  84      * contains the total size of the buffer for all channels.
  85      *
  86      * Note: Both data and extended_data should always be set in a valid frame,
  87      * but for planar audio with more channels that can fit in data,
  88      * extended_data must be used in order to access all channels.
  89      */
  90     uint8_t **extended_data;
  91
  92     /**
  93      * width and height of the video frame
  94      */
  95     int width, height;
  96
  97     /**
  98      * number of audio samples (per channel) described by this frame
  99      */
 100     int nb_samples;
 101
 102     /**
 103      * format of the frame, -1 if unknown or unset
 104      * Values correspond to enum AVPixelFormat for video frames,
 105      * enum AVSampleFormat for audio)
 106      */
 107     int format;
 108
 109     /**
 110      * 1 -> keyframe, 0-> not
 111      */
 112     int key_frame;
 113
 114     /**
 115      * Picture type of the frame.
 116      */
 117     enum AVPictureType pict_type;
 118
 119     uint8_t *base[AV_NUM_DATA_POINTERS];
 120
 121     /**
 122      * Sample aspect ratio for the video frame, 0/1 if unknown/unspecified.
 123      */
 124     AVRational sample_aspect_ratio;
 125
 126     /**
 127      * Presentation timestamp in time_base units (time when frame should be shown to user).
 128      */
 129     int64_t pts;
 130
 131     /**
 132      * PTS copied from the AVPacket that was decoded to produce this frame.
 133      */
 134     int64_t pkt_pts;
 135
 136     /**
 137      * DTS copied from the AVPacket that triggered returning this frame.
 138      */
 139     int64_t pkt_dts;
 140
 141     /**
 142      * picture number in bitstream order
 143      */
 144     int coded_picture_number;
 145     /**
 146      * picture number in display order
 147      */
 148     int display_picture_number;
 149
 150     /**
 151      * quality (between 1 (good) and FF_LAMBDA_MAX (bad))
 152      */
 153     int quality;
 154
 155     int reference;
 156
 157     /**
 158      * QP table
 159      */
 160     int8_t *qscale_table;
 161     /**
 162      * QP store stride
 163      */
 164     int qstride;
 165
 166     int qscale_type;
 167
 168     /**
 169      * mbskip_table[mb]>=1 if MB didn't change
 170      * stride= mb_width = (width+15)>>4
 171      */
 172     uint8_t *mbskip_table;
 173
 174     /**
 175      * motion vector table
 176      * @code
 177      * example:
 178      * int mv_sample_log2= 4 - motion_subsample_log2;
 179      * int mb_width= (width+15)>>4;
 180      * int mv_stride= (mb_width << mv_sample_log2) + 1;
 181      * motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];
 182      * @endcode
 183      */
 184     int16_t (*motion_val[2])[2];
 185
 186     /**
 187      * macroblock type table
 188      * mb_type_base + mb_width + 2
 189      */
 190     uint32_t *mb_type;
 191
 192     /**
 193      * DCT coefficients
 194      */
 195     short *dct_coeff;
 196
 197     /**
 198      * motion reference frame index
 199      * the order in which these are stored can depend on the codec.
 200      */
 201     int8_t *ref_index[2];
 202
 203     /**
 204      * for some private data of the user
 205      */
 206     void *opaque;
 207
 208     /**
 209      * error
 210      */
 211     uint64_t error[AV_NUM_DATA_POINTERS];
 212
 213     int type;
 214
 215     /**
 216      * When decoding, this signals how much the picture must be delayed.
 217      * extra_delay = repeat_pict / (2*fps)
 218      */
 219     int repeat_pict;
 220
 221     /**
 222      * The content of the picture is interlaced.
 223      */
 224     int interlaced_frame;
 225
 226     /**
 227      * If the content is interlaced, is top field displayed first.
 228      */
 229     int top_field_first;
 230
 231     /**
 232      * Tell user application that palette has changed from previous frame.
 233      */
 234     int palette_has_changed;
 235
 236     int buffer_hints;
 237
 238     /**
 239      * Pan scan.
 240      */
 241     struct AVPanScan *pan_scan;
 242
 243     /**
 244      * reordered opaque 64bit (generally an integer or a double precision float
 245      * PTS but can be anything).
 246      * The user sets AVCodecContext.reordered_opaque to represent the input at
 247      * that time,
 248      * the decoder reorders values as needed and sets AVFrame.reordered_opaque
 249      * to exactly one of the values provided by the user through AVCodecContext.reordered_opaque
 250      * @deprecated in favor of pkt_pts
 251      */
 252     int64_t reordered_opaque;
 253
 254 #if FF_API_AVFRAME_LAVC
 255     /**
 256      * @deprecated this field is unused
 257      */
 258     attribute_deprecated void *hwaccel_picture_private;
 259 #endif
 260
 261     struct AVCodecContext *owner;
 262     void *thread_opaque;
 263
 264     /**
 265      * log2 of the size of the block which a single vector in motion_val represents:
 266      * (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)
 267      */
 268     uint8_t motion_subsample_log2;
 269
 270     /**
 271      * Sample rate of the audio data.
 272      */
 273     int sample_rate;
 274
 275     /**
 276      * Channel layout of the audio data.
 277      */
 278     uint64_t channel_layout;
 279
 280     /**
 281      * AVBuffer references backing the data for this frame. If all elements of
 282      * this array are NULL, then this frame is not reference counted.
 283      *
 284      * There may be at most one AVBuffer per data plane, so for video this array
 285      * always contains all the references. For planar audio with more than
 286      * AV_NUM_DATA_POINTERS channels, there may be more buffers than can fit in
 287      * this array. Then the extra AVBufferRef pointers are stored in the
 288      * extended_buf array.
 289      */
 290     AVBufferRef *buf[AV_NUM_DATA_POINTERS];
 291
 292     /**
 293      * For planar audio which requires more than AV_NUM_DATA_POINTERS
 294      * AVBufferRef pointers, this array will hold all the references which
 295      * cannot fit into AVFrame.buf.
 296      *
 297      * Note that this is different from AVFrame.extended_data, which always
 298      * contains all the pointers. This array only contains the extra pointers,
 299      * which cannot fit into AVFrame.buf.
 300      *
 301      * This array is always allocated using av_malloc() by whoever constructs
 302      * the frame. It is freed in av_frame_unref().
 303      */
 304     AVBufferRef **extended_buf;
 305     /**
 306      * Number of elements in extended_buf.
 307      */
 308     int        nb_extended_buf;
 309 } AVFrame;
 310
 311 /**
 312  * Allocate an AVFrame and set its fields to default values.  The resulting
 313  * struct must be freed using av_frame_free().
 314  *
 315  * @return An AVFrame filled with default values or NULL on failure.
 316  *
 317  * @note this only allocates the AVFrame itself, not the data buffers. Those
 318  * must be allocated through other means, e.g. with av_frame_get_buffer() or
 319  * manually.
 320  */
 321 AVFrame *av_frame_alloc(void);
 322
 323 /**
 324  * Free the frame and any dynamically allocated objects in it,
 325  * e.g. extended_data. If the frame is reference counted, it will be
 326  * unreferenced first.
 327  *
 328  * @param frame frame to be freed. The pointer will be set to NULL.
 329  */
 330 void av_frame_free(AVFrame **frame);
 331
 332 /**
 333  * Setup a new reference to the data described by an given frame.
 334  *
 335  * Copy frame properties from src to dst and create a new reference for each
 336  * AVBufferRef from src.
 337  *
 338  * If src is not reference counted, new buffers are allocated and the data is
 339  * copied.
 340  *
 341  * @return 0 on success, a negative AVERROR on error
 342  */
 343 int av_frame_ref(AVFrame *dst, AVFrame *src);
 344
 345 /**
 346  * Create a new frame that references the same data as src.
 347  *
 348  * This is a shortcut for av_frame_alloc()+av_frame_ref().
 349  *
 350  * @return newly created AVFrame on success, NULL on error.
 351  */
 352 AVFrame *av_frame_clone(AVFrame *src);
 353
 354 /**
 355  * Unreference all the buffers referenced by frame and reset the frame fields.
 356  */
 357 void av_frame_unref(AVFrame *frame);
 358
 359 /**
 360  * Move everythnig contained in src to dst and reset src.
 361  */
 362 void av_frame_move_ref(AVFrame *dst, AVFrame *src);
 363
 364 /**
 365  * Allocate new buffer(s) for audio or video data.
 366  *
 367  * The following fields must be set on frame before calling this function:
 368  * - format (pixel format for video, sample format for audio)
 369  * - width and height for video
 370  * - nb_samples and channel_layout for audio
 371  *
 372  * This function will fill AVFrame.data and AVFrame.buf arrays and, if
 373  * necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
 374  * For planar formats, one buffer will be allocated for each plane.
 375  *
 376  * @param frame frame in which to store the new buffers.
 377  * @param align required buffer size alignment
 378  *
 379  * @return 0 on success, a negative AVERROR on error.
 380  */
 381 int av_frame_get_buffer(AVFrame *frame, int align);
 382
 383 /**
 384  * Check if the frame data is writable.
 385  *
 386  * @return A positive value if the frame data is writable (which is true if and
 387  * only if each of the underlying buffers has only one reference, namely the one
 388  * stored in this frame). Return 0 otherwise.
 389  *
 390  * If 1 is returned the answer is valid until av_buffer_ref() is called on any
 391  * of the underlying AVBufferRefs (e.g. through av_frame_ref() or directly).
 392  *
 393  * @see av_frame_make_writable(), av_buffer_is_writable()
 394  */
 395 int av_frame_is_writable(AVFrame *frame);
 396
 397 /**
 398  * Ensure that the frame data is writable, avoiding data copy if possible.
 399  *
 400  * Do nothing if the frame is writable, allocate new buffers and copy the data
 401  * if it is not.
 402  *
 403  * @return 0 on success, a negative AVERROR on error.
 404  *
 405  * @see av_frame_is_writable(), av_buffer_is_writable(),
 406  * av_buffer_make_writable()
 407  */
 408 int av_frame_make_writable(AVFrame *frame);
 409
 410 /**
 411  * Copy only "metadata" fields from src to dst.
 412  *
 413  * Metadata for the purpose of this function are those fields that do not affect
 414  * the data layout in the buffers.  E.g. pts, sample rate (for audio) or sample
 415  * aspect ratio (for video), but not width/height or channel layout.
 416  */
 417 int av_frame_copy_props(AVFrame *dst, const AVFrame *src);
 418
 419 /**
 420  * Get the buffer reference a given data plane is stored in.
 421  *
 422  * @param plane index of the data plane of interest in frame->extended_data.
 423  *
 424  * @return the buffer reference that contains the plane or NULL if the input
 425  * frame is not valid.
 426  */
 427 AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane);
 428
 429 #endif /* AVUTIL_FRAME_H */