/*** @}* @}* @defgroup lavu_picture Image related** AVPicture types, pixel formats and basic image planes manipulation.** @{*/enum AVPictureType {AV_PICTURE_TYPE_NONE = 0, ///< UndefinedAV_PICTURE_TYPE_I,     ///< IntraAV_PICTURE_TYPE_P,     ///< PredictedAV_PICTURE_TYPE_B,     ///< Bi-dir predictedAV_PICTURE_TYPE_S,     ///< S(GMC)-VOP MPEG-4AV_PICTURE_TYPE_SI,    ///< Switching IntraAV_PICTURE_TYPE_SP,    ///< Switching PredictedAV_PICTURE_TYPE_BI,    ///< BI type
};

/*** @defgroup lavu_math_rational AVRational* @ingroup lavu_math* Rational number calculation.** While rational numbers can be expressed as floating-point numbers, the* conversion process is a lossy one, so are floating-point operations. On the* other hand, the nature of FFmpeg demands highly accurate calculation of* timestamps. This set of rational number utilities serves as a generic* interface for manipulating rational numbers as pairs of numerators and* denominators.** Many of the functions that operate on AVRational's have the suffix `_q`, in* reference to the mathematical symbol "鈩 (Q) which denotes the set of all* rational numbers.** @{*//*** Rational number (pair of numerator and denominator).*/
typedef struct AVRational{int num; ///< Numeratorint den; ///< Denominator
} AVRational;

/*** Picture.*/
typedef struct Picture {struct AVFrame *f;ThreadFrame tf;AVBufferRef *qscale_table_buf;int8_t *qscale_table;AVBufferRef *motion_val_buf[2];int16_t (*motion_val[2])[2];AVBufferRef *mb_type_buf;uint32_t *mb_type;          ///< types and macros are defined in mpegutils.hAVBufferRef *mbskip_table_buf;uint8_t *mbskip_table;AVBufferRef *ref_index_buf[2];int8_t *ref_index[2];AVBufferRef *mb_var_buf;uint16_t *mb_var;           ///< Table for MB variancesAVBufferRef *mc_mb_var_buf;uint16_t *mc_mb_var;        ///< Table for motion compensated MB variancesint alloc_mb_width;         ///< mb_width used to allocate tablesint alloc_mb_height;        ///< mb_height used to allocate tablesint alloc_mb_stride;        ///< mb_stride used to allocate tablesAVBufferRef *mb_mean_buf;uint8_t *mb_mean;           ///< Table for MB luminanceAVBufferRef *hwaccel_priv_buf;void *hwaccel_picture_private; ///< Hardware accelerator private dataint field_picture;          ///< whether or not the picture was encoded in separate fieldsint64_t mb_var_sum;         ///< sum of MB variance for current frameint64_t mc_mb_var_sum;      ///< motion compensated MB variance for current frameint b_frame_score;int needs_realloc;          ///< Picture needs to be reallocated (eg due to a frame size change)int reference;int shared;uint64_t encoding_error[MPEGVIDEO_MAX_PLANES];
} Picture;

typedef struct ERPicture {AVFrame *f;ThreadFrame *tf;// it is the caller's responsibility to allocate these buffersint16_t (*motion_val[2])[2];int8_t *ref_index[2];uint32_t *mb_type;int field_picture;
} ERPicture;

int mv_sample_log2= 4 - motion_subsample_log2;
int mb_width= (width+15)>>4;
int mv_stride= (mb_width << mv_sample_log2) + 1;
motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];

//例如8x8划分的运动矢量与宏块的关系：//-------------------------//|          |            |//|mv[x]     |mv[x+1]     |//-------------------------//|          |	          |//|mv[x+line]|mv[x+line+1]|//-------------------------

/* MB types */
#define MB_TYPE_INTRA4x4   (1 <<  0)
#define MB_TYPE_INTRA16x16 (1 <<  1) // FIXME H.264-specific
#define MB_TYPE_INTRA_PCM  (1 <<  2) // FIXME H.264-specific
#define MB_TYPE_16x16      (1 <<  3)
#define MB_TYPE_16x8       (1 <<  4)
#define MB_TYPE_8x16       (1 <<  5)
#define MB_TYPE_8x8        (1 <<  6)
#define MB_TYPE_INTERLACED (1 <<  7)
#define MB_TYPE_DIRECT2    (1 <<  8) // FIXME
#define MB_TYPE_ACPRED     (1 <<  9)
#define MB_TYPE_GMC        (1 << 10)
#define MB_TYPE_SKIP       (1 << 11)
#define MB_TYPE_P0L0       (1 << 12)
#define MB_TYPE_P1L0       (1 << 13)
#define MB_TYPE_P0L1       (1 << 14)
#define MB_TYPE_P1L1       (1 << 15)
#define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
#define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
#define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
#define MB_TYPE_QUANT      (1 << 16)
#define MB_TYPE_CBP        (1 << 17)#define MB_TYPE_INTRA    MB_TYPE_INTRA4x4 // default mb_type if there is just one type

typedef struct AVFrame {
#define AV_NUM_DATA_POINTERS 8/*** pointer to the picture/channel planes.* This might be different from the first allocated byte. For video,* it could even point to the end of the image data.** All pointers in data and extended_data must point into one of the* AVBufferRef in buf or extended_buf.** 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: Pointers not needed by the format MUST be set to NULL.** @attention In case of video, the data[] pointers can point to the* end of image data in order to reverse line order, when used in* combination with negative values in the linesize[] array.*/uint8_t *data[AV_NUM_DATA_POINTERS];/*** For video, a positive or negative value, which is typically indicating* the size in bytes of each picture line, but it can also be:* - the negative byte size of lines for vertical flipping*   (with data[n] pointing to the end of the data* - a positive or negative multiple of the byte size as for accessing*   even and odd fields of a frame (possibly flipped)** 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.** @attention In case of video, line size values can be negative to achieve* a vertically inverted iteration over image lines.*/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;/*** 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;/*** Time base for the timestamps in this frame.* In the future, this field may be set on frames output by decoders or* filters, but its value will be by default ignored on input to encoders* or filters.*/AVRational time_base;/*** 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;/*** 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;#if FF_API_OLD_CHANNEL_LAYOUT/*** Channel layout of the audio data.* @deprecated use ch_layout instead*/attribute_deprecateduint64_t channel_layout;
#endif/*** AVBuffer references backing the data for this frame. All the pointers in* data and extended_data must point inside one of the buffers in buf or* extended_buf. 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
#define FF_DECODE_ERROR_CONCEALMENT_ACTIVE  4
#define FF_DECODE_ERROR_DECODE_SLICES       8#if FF_API_OLD_CHANNEL_LAYOUT/*** number of audio channels, only used for audio.* - encoding: unused* - decoding: Read by user.* @deprecated use ch_layout instead*/attribute_deprecatedint channels;
#endif/*** 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;/*** 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;/*** Channel layout of the audio data.*/AVChannelLayout ch_layout;
} AVFrame;