text: /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * @ingroup lavu_frame
   * reference-counted frame API
   */
  
  #ifndef AVUTIL_FRAME_H
  #define AVUTIL_FRAME_H
  
  #include <stddef.h>
  #include <stdint.h>
  
  #include "avutil.h"
  #include "buffer.h"
  #include "dict.h"
  #include "rational.h"
  #include "samplefmt.h"
  #include "pixfmt.h"
  #include "version.h"
  
  
  /**
   * @defgroup lavu_frame AVFrame
   * @ingroup lavu_data
   *
   * @{
   * AVFrame is an abstraction for reference-counted raw multimedia data.
   */
  
  enum AVFrameSideDataType {
      /**
       * The data is the AVPanScan struct defined in libavcodec.
       */
      AV_FRAME_DATA_PANSCAN,
      /**
       * ATSC A53 Part 4 Closed Captions.
       * A53 CC bitstream is stored as uint8_t in AVFrameSideData.data.
       * The number of bytes of CC data is AVFrameSideData.size.
       */
      AV_FRAME_DATA_A53_CC,
      /**
       * Stereoscopic 3d metadata.
       * The data is the AVStereo3D struct defined in libavutil/stereo3d.h.
       */
      AV_FRAME_DATA_STEREO3D,
      /**
       * The data is the AVMatrixEncoding enum defined in libavutil/channel_layout.h.
       */
      AV_FRAME_DATA_MATRIXENCODING,
      /**
       * Metadata relevant to a downmix procedure.
       * The data is the AVDownmixInfo struct defined in libavutil/downmix_info.h.
       */
      AV_FRAME_DATA_DOWNMIX_INFO,
      /**
       * ReplayGain information in the form of the AVReplayGain struct.
       */
      AV_FRAME_DATA_REPLAYGAIN,
      /**
       * This side data contains a 3x3 transformation matrix describing an affine
       * transformation that needs to be applied to the frame for correct
       * presentation.
       *
       * See libavutil/display.h for a detailed description of the data.
       */
      AV_FRAME_DATA_DISPLAYMATRIX,
      /**
       * Active Format Description data consisting of a single byte as specified
       * in ETSI TS 101 154 using AVActiveFormatDescription enum.
       */
      AV_FRAME_DATA_AFD,
      /**
       * Motion vectors exported by some codecs (on demand through the export_mvs
       * flag set in the libavcodec AVCodecContext flags2 option).
       * The data is the AVMotionVector struct defined in
       * libavutil/motion_vector.h.
       */
      AV_FRAME_DATA_MOTION_VECTORS,
      /**
       * Recommmends skipping the specified number of samples. This is exported
       * only if the "skip_manual" AVOption is set in libavcodec.
       * This has the same format as AV_PKT_DATA_SKIP_SAMPLES.
       * @code
       * u32le number of samples to skip from start of this packet
       * u32le number of samples to skip from end of this packet
       * u8    reason for start skip
       * u8    reason for end   skip (0=padding silence, 1=convergence)
       * @endcode
       */
      AV_FRAME_DATA_SKIP_SAMPLES,
      /**
       * This side data must be associated with an audio frame and corresponds to
       * enum AVAudioServiceType defined in avcodec.h.
       */
      AV_FRAME_DATA_AUDIO_SERVICE_TYPE,
      /**
       * Mastering display metadata associated with a video frame. The payload is
       * an AVMasteringDisplayMetadata type and contains information about the
       * mastering display color volume.
       */
      AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
      /**
       * The GOP timecode in 25 bit timecode format. Data format is 64-bit integer.
       * This is set on the first frame of a GOP that has a temporal reference of 0.
       */
      AV_FRAME_DATA_GOP_TIMECODE,
  
      /**
       * The data represents the AVSphericalMapping structure defined in
       * libavutil/spherical.h.
       */
      AV_FRAME_DATA_SPHERICAL,
  
      /**
       * Content light level (based on CTA-861.3). This payload contains data in
       * the form of the AVContentLightMetadata struct.
       */
      AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,
  
      /**
       * The data contains an ICC profile as an opaque octet buffer following the
       * format described by ISO 15076-1 with an optional name defined in the
       * metadata key entry "name".
       */
      AV_FRAME_DATA_ICC_PROFILE,
  
  #if FF_API_FRAME_QP
      /**
       * Implementation-specific description of the format of AV_FRAME_QP_TABLE_DATA.
       * The contents of this side data are undocumented and internal; use
       * av_frame_set_qp_table() and av_frame_get_qp_table() to access this in a
       * meaningful way instead.
       */
      AV_FRAME_DATA_QP_TABLE_PROPERTIES,
  
      /**
       * Raw QP table data. Its format is described by
       * AV_FRAME_DATA_QP_TABLE_PROPERTIES. Use av_frame_set_qp_table() and
       * av_frame_get_qp_table() to access this instead.
       */
      AV_FRAME_DATA_QP_TABLE_DATA,
  #endif
  
      /**
       * Timecode which conforms to SMPTE ST 12-1. The data is an array of 4 uint32_t
       * where the first uint32_t describes how many (1-3) of the other timecodes are used.
       * The timecode format is described in the av_timecode_get_smpte_from_framenum()
       * function in libavutil/timecode.c.
       */
      AV_FRAME_DATA_S12M_TIMECODE,
  };
  
  enum AVActiveFormatDescription {
      AV_AFD_SAME         = 8,
      AV_AFD_4_3          = 9,
      AV_AFD_16_9         = 10,
      AV_AFD_14_9         = 11,
      AV_AFD_4_3_SP_14_9  = 13,
      AV_AFD_16_9_SP_14_9 = 14,
      AV_AFD_SP_4_3       = 15,
  };
  
  
  /**
   * Structure to hold side data for an AVFrame.
   *
   * sizeof(AVFrameSideData) is not a part of the public ABI, so new fields may be added
   * to the end with a minor bump.
   */
  typedef struct AVFrameSideData {
      enum AVFrameSideDataType type;
      uint8_t *data;
      int      size;
      AVDictionary *metadata;
      AVBufferRef *buf;
  } AVFrameSideData;
  
  /**
   * This structure describes decoded (raw) audio or video data.
   *
   * AVFrame must be allocated using av_frame_alloc(). Note that this only
   * allocates the AVFrame itself, the buffers for the data must be managed
   * through other means (see below).
   * AVFrame must be freed with av_frame_free().
   *
   * AVFrame is typically allocated once and then reused multiple times to hold
   * different data (e.g. a single AVFrame to hold frames received from a
   * decoder). In such a case, av_frame_unref() will free any references held by
   * the frame and reset it to its original clean state before it
   * is reused again.
   *
   * The data described by an AVFrame is usually reference counted through the
   * AVBuffer API. The underlying buffer references are stored in AVFrame.buf /
   * AVFrame.extended_buf. An AVFrame is considered to be reference counted if at
   * least one reference is set, i.e. if AVFrame.buf[0] != NULL. In such a case,
   * every single data plane must be contained in one of the buffers in
   * AVFrame.buf or AVFrame.extended_buf.
   * There may be a single buffer for all the data, or one separate buffer for
   * each plane, or anything in between.
   *
   * sizeof(AVFrame) is not a part of the public ABI, so new fields may be added
   * to the end with a minor bump.
   *
   * Fields can be accessed through AVOptions, the name string used, matches the
   * C structure field name for fields accessible through AVOptions. The AVClass
   * for AVFrame can be obtained from avcodec_get_frame_class()
   */
  typedef struct AVFrame {
  #define AV_NUM_DATA_POINTERS 8
      /**
       * pointer to the picture/channel planes.
       * This might be different from the first allocated byte
       *
       * Some decoders access areas outside 0,0 - width,height, please
       * see avcodec_align_dimensions2(). Some filters and swscale can read
       * up to 16 bytes beyond the planes, if these filters are to be used,
       * then 16 extra bytes must be allocated.
       *
       * NOTE: Except for hwaccel formats, pointers not needed by the format
       * MUST be set to NULL.
       */
      uint8_t *data[AV_NUM_DATA_POINTERS];
  
      /**
       * For video, size in bytes of each picture line.
       * For audio, size in bytes of each plane.
       *
       * For audio, only linesize[0] may be set. For planar audio, each channel
       * plane must be the same size.
       *
       * For video the linesizes should be multiples of the CPUs alignment
       * preference, this is 16 or 32 for modern desktop CPUs.
       * Some code requires such alignment other code can be slower without
       * correct alignment, for yet other it makes no difference.
       *
       * @note The linesize may be larger than the size of usable data -- there
       * may be extra padding present for performance reasons.
       */
      int linesize[AV_NUM_DATA_POINTERS];
  
      /**
       * pointers to the data planes/channels.
       *
       * For video, this should simply point to data[].
       *
       * For planar audio, each channel has a separate data pointer, and
       * linesize[0] contains the size of each channel buffer.
       * For packed audio, there is just one data pointer, and linesize[0]
       * contains the total size of the buffer for all channels.
       *
       * Note: Both data and extended_data should always be set in a valid frame,
       * but for planar audio with more channels that can fit in data,
       * extended_data must be used in order to access all channels.
       */
      uint8_t **extended_data;
  
      /**
       * @name Video dimensions
       * Video frames only. The coded dimensions (in pixels) of the video frame,
       * i.e. the size of the rectangle that contains some well-defined values.
       *
       * @note The part of the frame intended for display/presentation is further
       * restricted by the @ref cropping "Cropping rectangle".
       * @{
       */
      int width, height;
      /**
       * @}
       */
  
      /**
       * number of audio samples (per channel) described by this frame
       */
      int nb_samples;
  
      /**
       * format of the frame, -1 if unknown or unset
       * Values correspond to enum AVPixelFormat for video frames,
       * enum AVSampleFormat for audio)
       */
      int format;
  
      /**
       * 1 -> keyframe, 0-> not
       */
      int key_frame;
  
      /**
       * Picture type of the frame.
       */
      enum AVPictureType pict_type;
  
      /**
       * Sample aspect ratio for the video frame, 0/1 if unknown/unspecified.
       */
      AVRational sample_aspect_ratio;
  
      /**
       * Presentation timestamp in time_base units (time when frame should be shown to user).
       */
      int64_t pts;
  
  #if FF_API_PKT_PTS
      /**
       * PTS copied from the AVPacket that was decoded to produce this frame.
       * @deprecated use the pts field instead
       */
      attribute_deprecated
      int64_t pkt_pts;
  #endif
  
      /**
       * DTS copied from the AVPacket that triggered returning this frame. (if frame threading isn't used)
       * This is also the Presentation time of this AVFrame calculated from
       * only AVPacket.dts values without pts values.
       */
      int64_t pkt_dts;
  
      /**
       * picture number in bitstream order
       */
      int coded_picture_number;
      /**
       * picture number in display order
       */
      int display_picture_number;
  
      /**
       * quality (between 1 (good) and FF_LAMBDA_MAX (bad))
       */
      int quality;
  
      /**
       * for some private data of the user
       */
      void *opaque;
  
  #if FF_API_ERROR_FRAME
      /**
       * @deprecated unused
       */
      attribute_deprecated
      uint64_t error[AV_NUM_DATA_POINTERS];
  #endif
  
      /**
       * When decoding, this signals how much the picture must be delayed.
       * extra_delay = repeat_pict / (2*fps)
       */
      int repeat_pict;
  
      /**
       * The content of the picture is interlaced.
       */
      int interlaced_frame;
  
      /**
       * If the content is interlaced, is top field displayed first.
       */
      int top_field_first;
  
      /**
       * Tell user application that palette has changed from previous frame.
       */
      int palette_has_changed;
  
      /**
       * reordered opaque 64 bits (generally an integer or a double precision float
       * PTS but can be anything).
       * The user sets AVCodecContext.reordered_opaque to represent the input at
       * that time,
       * the decoder reorders values as needed and sets AVFrame.reordered_opaque
       * to exactly one of the values provided by the user through AVCodecContext.reordered_opaque
       */
      int64_t reordered_opaque;
  
      /**
       * Sample rate of the audio data.
       */
      int sample_rate;
  
      /**
       * Channel layout of the audio data.
       */
      uint64_t channel_layout;
  
      /**
       * AVBuffer references backing the data for this frame. If all elements of
       * this array are NULL, then this frame is not reference counted. This array
       * must be filled contiguously -- if buf[i] is non-NULL then buf[j] must
       * also be non-NULL for all j < i.
       *
       * There may be at most one AVBuffer per data plane, so for video this array
       * always contains all the references. For planar audio with more than
       * AV_NUM_DATA_POINTERS channels, there may be more buffers than can fit in
       * this array. Then the extra AVBufferRef pointers are stored in the
       * extended_buf array.
       */
      AVBufferRef *buf[AV_NUM_DATA_POINTERS];
  
      /**
       * For planar audio which requires more than AV_NUM_DATA_POINTERS
       * AVBufferRef pointers, this array will hold all the references which
       * cannot fit into AVFrame.buf.
       *
       * Note that this is different from AVFrame.extended_data, which always
       * contains all the pointers. This array only contains the extra pointers,
       * which cannot fit into AVFrame.buf.
       *
       * This array is always allocated using av_malloc() by whoever constructs
       * the frame. It is freed in av_frame_unref().
       */
      AVBufferRef **extended_buf;
      /**
       * Number of elements in extended_buf.
       */
      int        nb_extended_buf;
  
      AVFrameSideData **side_data;
      int            nb_side_data;
  
  /**
   * @defgroup lavu_frame_flags AV_FRAME_FLAGS
   * @ingroup lavu_frame
   * Flags describing additional frame properties.
   *
   * @{
   */
  
  /**
   * The frame data may be corrupted, e.g. due to decoding errors.
   */
  #define AV_FRAME_FLAG_CORRUPT       (1 << 0)
  /**
   * A flag to mark the frames which need to be decoded, but shouldn't be output.
   */
  #define AV_FRAME_FLAG_DISCARD   (1 << 2)
  /**
   * @}
   */
  
      /**
       * Frame flags, a combination of @ref lavu_frame_flags
       */
      int flags;
  
      /**
       * MPEG vs JPEG YUV range.
       * - encoding: Set by user
       * - decoding: Set by libavcodec
       */
      enum AVColorRange color_range;
  
      enum AVColorPrimaries color_primaries;
  
      enum AVColorTransferCharacteristic color_trc;
  
      /**
       * YUV colorspace type.
       * - encoding: Set by user
       * - decoding: Set by libavcodec
       */
      enum AVColorSpace colorspace;
  
      enum AVChromaLocation chroma_location;
  
      /**
       * frame timestamp estimated using various heuristics, in stream time base
       * - encoding: unused
       * - decoding: set by libavcodec, read by user.
       */
      int64_t best_effort_timestamp;
  
      /**
       * reordered pos from the last AVPacket that has been input into the decoder
       * - encoding: unused
       * - decoding: Read by user.
       */
      int64_t pkt_pos;
  
      /**
       * duration of the corresponding packet, expressed in
       * AVStream->time_base units, 0 if unknown.
       * - encoding: unused
       * - decoding: Read by user.
       */
      int64_t pkt_duration;
  
      /**
       * metadata.
       * - encoding: Set by user.
       * - decoding: Set by libavcodec.
       */
      AVDictionary *metadata;
  
      /**
       * decode error flags of the frame, set to a combination of
       * FF_DECODE_ERROR_xxx flags if the decoder produced a frame, but there
       * were errors during the decoding.
       * - encoding: unused
       * - decoding: set by libavcodec, read by user.
       */
      int decode_error_flags;
  #define FF_DECODE_ERROR_INVALID_BITSTREAM   1
  #define FF_DECODE_ERROR_MISSING_REFERENCE   2
  
      /**
       * number of audio channels, only used for audio.
       * - encoding: unused
       * - decoding: Read by user.
       */
      int channels;
  
      /**
       * size of the corresponding packet containing the compressed
       * frame.
       * It is set to a negative value if unknown.
       * - encoding: unused
       * - decoding: set by libavcodec, read by user.
       */
      int pkt_size;
  
  #if FF_API_FRAME_QP
      /**
       * QP table
       */
      attribute_deprecated
      int8_t *qscale_table;
      /**
       * QP store stride
       */
      attribute_deprecated
      int qstride;
  
      attribute_deprecated
      int qscale_type;
  
      attribute_deprecated
      AVBufferRef *qp_table_buf;
  #endif
      /**
       * For hwaccel-format frames, this should be a reference to the
       * AVHWFramesContext describing the frame.
       */
      AVBufferRef *hw_frames_ctx;
  
      /**
       * AVBufferRef for free use by the API user. FFmpeg will never check the
       * contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
       * the frame is unreferenced. av_frame_copy_props() calls create a new
       * reference with av_buffer_ref() for the target frame's opaque_ref field.
       *
       * This is unrelated to the opaque field, although it serves a similar
       * purpose.
       */
      AVBufferRef *opaque_ref;
  
      /**
       * @anchor cropping
       * @name Cropping
       * Video frames only. The number of pixels to discard from the the
       * top/bottom/left/right border of the frame to obtain the sub-rectangle of
       * the frame intended for presentation.
       * @{
       */
      size_t crop_top;
      size_t crop_bottom;
      size_t crop_left;
      size_t crop_right;
      /**
       * @}
       */
  
      /**
       * AVBufferRef for internal use by a single libav* library.
       * Must not be used to transfer data between libraries.
       * Has to be NULL when ownership of the frame leaves the respective library.
       *
       * Code outside the FFmpeg libs should never check or change the contents of the buffer ref.
       *
       * FFmpeg calls av_buffer_unref() on it when the frame is unreferenced.
       * av_frame_copy_props() calls create a new reference with av_buffer_ref()
       * for the target frame's private_ref field.
       */
      AVBufferRef *private_ref;
  } AVFrame;
  
  #if FF_API_FRAME_GET_SET
  /**
   * Accessors for some AVFrame fields. These used to be provided for ABI
   * compatibility, and do not need to be used anymore.
   */
  attribute_deprecated
  int64_t av_frame_get_best_effort_timestamp(const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_best_effort_timestamp(AVFrame *frame, int64_t val);
  attribute_deprecated
  int64_t av_frame_get_pkt_duration         (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_pkt_duration         (AVFrame *frame, int64_t val);
  attribute_deprecated
  int64_t av_frame_get_pkt_pos              (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_pkt_pos              (AVFrame *frame, int64_t val);
  attribute_deprecated
  int64_t av_frame_get_channel_layout       (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_channel_layout       (AVFrame *frame, int64_t val);
  attribute_deprecated
  int     av_frame_get_channels             (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_channels             (AVFrame *frame, int     val);
  attribute_deprecated
  int     av_frame_get_sample_rate          (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_sample_rate          (AVFrame *frame, int     val);
  attribute_deprecated
  AVDictionary *av_frame_get_metadata       (const AVFrame *frame);
  attribute_deprecated
  void          av_frame_set_metadata       (AVFrame *frame, AVDictionary *val);
  attribute_deprecated
  int     av_frame_get_decode_error_flags   (const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_decode_error_flags   (AVFrame *frame, int     val);
  attribute_deprecated
  int     av_frame_get_pkt_size(const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_pkt_size(AVFrame *frame, int val);
  #if FF_API_FRAME_QP
  attribute_deprecated
  int8_t *av_frame_get_qp_table(AVFrame *f, int *stride, int *type);
  attribute_deprecated
  int av_frame_set_qp_table(AVFrame *f, AVBufferRef *buf, int stride, int type);
  #endif
  attribute_deprecated
  enum AVColorSpace av_frame_get_colorspace(const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_colorspace(AVFrame *frame, enum AVColorSpace val);
  attribute_deprecated
  enum AVColorRange av_frame_get_color_range(const AVFrame *frame);
  attribute_deprecated
  void    av_frame_set_color_range(AVFrame *frame, enum AVColorRange val);
  #endif
  
  /**
   * Get the name of a colorspace.
   * @return a static string identifying the colorspace; can be NULL.
   */
  const char *av_get_colorspace_name(enum AVColorSpace val);
  
  /**
   * Allocate an AVFrame and set its fields to default values.  The resulting
   * struct must be freed using av_frame_free().
   *
   * @return An AVFrame filled with default values or NULL on failure.
   *
   * @note this only allocates the AVFrame itself, not the data buffers. Those
   * must be allocated through other means, e.g. with av_frame_get_buffer() or
   * manually.
   */
  AVFrame *av_frame_alloc(void);
  
  /**
   * Free the frame and any dynamically allocated objects in it,
   * e.g. extended_data. If the frame is reference counted, it will be
   * unreferenced first.
   *
   * @param frame frame to be freed. The pointer will be set to NULL.
   */
  void av_frame_free(AVFrame **frame);
  
  /**
   * Set up a new reference to the data described by the source frame.
   *
   * Copy frame properties from src to dst and create a new reference for each
   * AVBufferRef from src.
   *
   * If src is not reference counted, new buffers are allocated and the data is
   * copied.
   *
   * @warning: dst MUST have been either unreferenced with av_frame_unref(dst),
   *           or newly allocated with av_frame_alloc() before calling this
   *           function, or undefined behavior will occur.
   *
   * @return 0 on success, a negative AVERROR on error
   */
  int av_frame_ref(AVFrame *dst, const AVFrame *src);
  
  /**
   * Create a new frame that references the same data as src.
   *
   * This is a shortcut for av_frame_alloc()+av_frame_ref().
   *
   * @return newly created AVFrame on success, NULL on error.
   */
  AVFrame *av_frame_clone(const AVFrame *src);
  
  /**
   * Unreference all the buffers referenced by frame and reset the frame fields.
   */
  void av_frame_unref(AVFrame *frame);
  
  /**
   * Move everything contained in src to dst and reset src.
   *
   * @warning: dst is not unreferenced, but directly overwritten without reading
   *           or deallocating its contents. Call av_frame_unref(dst) manually
   *           before calling this function to ensure that no memory is leaked.
   */
  void av_frame_move_ref(AVFrame *dst, AVFrame *src);
  
  /**
   * Allocate new buffer(s) for audio or video data.
   *
   * The following fields must be set on frame before calling this function:
   * - format (pixel format for video, sample format for audio)
   * - width and height for video
   * - nb_samples and channel_layout for audio
   *
   * This function will fill AVFrame.data and AVFrame.buf arrays and, if
   * necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
   * For planar formats, one buffer will be allocated for each plane.
   *
   * @warning: if frame already has been allocated, calling this function will
   *           leak memory. In addition, undefined behavior can occur in certain
   *           cases.
   *
   * @param frame frame in which to store the new buffers.
   * @param align Required buffer size alignment. If equal to 0, alignment will be
   *              chosen automatically for the current CPU. It is highly
   *              recommended to pass 0 here unless you know what you are doing.
   *
   * @return 0 on success, a negative AVERROR on error.
   */
  int av_frame_get_buffer(AVFrame *frame, int align);
  
  /**
   * Check if the frame data is writable.
   *
   * @return A positive value if the frame data is writable (which is true if and
   * only if each of the underlying buffers has only one reference, namely the one
   * stored in this frame). Return 0 otherwise.
   *
   * If 1 is returned the answer is valid until av_buffer_ref() is called on any
   * of the underlying AVBufferRefs (e.g. through av_frame_ref() or directly).
   *
   * @see av_frame_make_writable(), av_buffer_is_writable()
   */
  int av_frame_is_writable(AVFrame *frame);
  
  /**
   * Ensure that the frame data is writable, avoiding data copy if possible.
   *
   * Do nothing if the frame is writable, allocate new buffers and copy the data
   * if it is not.
   *
   * @return 0 on success, a negative AVERROR on error.
   *
   * @see av_frame_is_writable(), av_buffer_is_writable(),
   * av_buffer_make_writable()
   */
  int av_frame_make_writable(AVFrame *frame);
  
  /**
   * Copy the frame data from src to dst.
   *
   * This function does not allocate anything, dst must be already initialized and
   * allocated with the same parameters as src.
   *
   * This function only copies the frame data (i.e. the contents of the data /
   * extended data arrays), not any other properties.
   *
   * @return >= 0 on success, a negative AVERROR on error.
   */
  int av_frame_copy(AVFrame *dst, const AVFrame *src);
  
  /**
   * Copy only "metadata" fields from src to dst.
   *
   * Metadata for the purpose of this function are those fields that do not affect
   * the data layout in the buffers.  E.g. pts, sample rate (for audio) or sample
   * aspect ratio (for video), but not width/height or channel layout.
   * Side data is also copied.
   */
  int av_frame_copy_props(AVFrame *dst, const AVFrame *src);
  
  /**
   * Get the buffer reference a given data plane is stored in.
   *
   * @param plane index of the data plane of interest in frame->extended_data.
   *
   * @return the buffer reference that contains the plane or NULL if the input
   * frame is not valid.
   */
  AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane);
  
  /**
   * Add a new side data to a frame.
   *
   * @param frame a frame to which the side data should be added
   * @param type type of the added side data
   * @param size size of the side data
   *
   * @return newly added side data on success, NULL on error
   */
  AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
                                          enum AVFrameSideDataType type,
                                          int size);
  
  /**
   * Add a new side data to a frame from an existing AVBufferRef
   *
   * @param frame a frame to which the side data should be added
   * @param type  the type of the added side data
   * @param buf   an AVBufferRef to add as side data. The ownership of
   *              the reference is transferred to the frame.
   *
   * @return newly added side data on success, NULL on error. On failure
   *         the frame is unchanged and the AVBufferRef remains owned by
   *         the caller.
   */
  AVFrameSideData *av_frame_new_side_data_from_buf(AVFrame *frame,
                                                   enum AVFrameSideDataType type,
                                                   AVBufferRef *buf);
  
  /**
   * @return a pointer to the side data of a given type on success, NULL if there
   * is no side data with such type in this frame.
   */
  AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
                                          enum AVFrameSideDataType type);
  
  /**
   * If side data of the supplied type exists in the frame, free it and remove it
   * from the frame.
   */
  void av_frame_remove_side_data(AVFrame *frame, enum AVFrameSideDataType type);
  
  
  /**
   * Flags for frame cropping.
   */
  enum {
      /**
       * Apply the maximum possible cropping, even if it requires setting the
       * AVFrame.data[] entries to unaligned pointers. Passing unaligned data
       * to FFmpeg API is generally not allowed, and causes undefined behavior
       * (such as crashes). You can pass unaligned data only to FFmpeg APIs that
       * are explicitly documented to accept it. Use this flag only if you
       * absolutely know what you are doing.
       */
      AV_FRAME_CROP_UNALIGNED     = 1 << 0,
  };
  
  /**
   * Crop the given video AVFrame according to its crop_left/crop_top/crop_right/
   * crop_bottom fields. If cropping is successful, the function will adjust the
   * data pointers and the width/height fields, and set the crop fields to 0.
   *
   * In all cases, the cropping boundaries will be rounded to the inherent
   * alignment of the pixel format. In some cases, such as for opaque hwaccel
   * formats, the left/top cropping is ignored. The crop fields are set to 0 even
   * if the cropping was rounded or ignored.
   *
   * @param frame the frame which should be cropped
   * @param flags Some combination of AV_FRAME_CROP_* flags, or 0.
   *
   * @return >= 0 on success, a negative AVERROR on error. If the cropping fields
   * were invalid, AVERROR(ERANGE) is returned, and nothing is changed.
   */
  int av_frame_apply_cropping(AVFrame *frame, int flags);
  
  /**
   * @return a string identifying the side data type
   */
  const char *av_frame_side_data_name(enum AVFrameSideDataType type);
  
  /**
   * @}
   */
  
  #endif /* AVUTIL_FRAME_H */
  