/**该结构描述了解码的(原始)音频或视频数据。
*必须使用av_frame_alloc()(旧接口:avcodec_alloc_frame(),新接口:av_frame_alloc())分配AVFrame。请注意,这只是
*分配AVFrame本身,必须通过其他方式(见下文)管理数据的缓冲区;
*必须使用av_frame_free()释放AVFrame。
*
* AVFrame通常分配一次,然后多次重复使用以保存
*不同的数据(例如,单个AVFrame用于保存从一个解码器接收的帧)
*av_frame_unref()再次重复使用前将释放由其持有的任何引用框架并将其重置为之前的原始清洁状态
*一个AVFrame所描述的数据通常是通过参考AVBuffer API计算。内部的buffer引用存储在AVFrame.buf /AVFrame.extended_buf。
*AVFrame将用于引用计数,当至少一个引用被set时,如果AVFrame.buf[0] != NULL, 每个单个数据至少包含一个AVFrame.buf */AVFrame.extended_buf.可能会有一个缓冲的数据,或一个单独的缓冲对每个plane, 或介于两者之间的任何东西。
*sizeof(AVFrame)不是一个public的API,因此新的成员将被添加到末尾。同样字段标记为只访问av_opt_ptr()可以重新排序
*/
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.
*/
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;
/**
* width and height of the video frame
*/
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;
#if FF_API_AVFRAME_LAVC
attribute_deprecated
uint8_t *base[AV_NUM_DATA_POINTERS];
#endif
/**
* 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;
/**
* PTS copied from the AVPacket that was decoded to produce this frame.
*/
int64_t pkt_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;
/**
* 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;
#if FF_API_AVFRAME_LAVC
attribute_deprecated
int reference;
/**
* QP table
*/
attribute_deprecated
int8_t *qscale_table;
/**
* QP store stride
*/
attribute_deprecated
int qstride;
attribute_deprecated
int qscale_type;
/**
* mbskip_table[mb]>=1 if MB didn't change
* stride= mb_width = (width+15)>>4
*/
attribute_deprecated
uint8_t *mbskip_table;
/**
* motion vector table
* @code
* example:
* 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];
* @endcode
*/
int16_t (*motion_val[2])[2];
/**
* macroblock type table
* mb_type_base + mb_width + 2
*/
attribute_deprecated
uint32_t *mb_type;
/**
* DCT coefficients
*/
attribute_deprecated
short *dct_coeff;
/**
* motion reference frame index
* the order in which these are stored can depend on the codec.
*/
attribute_deprecated
int8_t *ref_index[2];
#endif
/**
* for some private data of the user
*/
void *opaque;
/**
* error
*/
uint64_t error[AV_NUM_DATA_POINTERS];
#if FF_API_AVFRAME_LAVC
attribute_deprecated
int type;
#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;
#if FF_API_AVFRAME_LAVC
attribute_deprecated
int buffer_hints;
/**
* Pan scan.
*/
attribute_deprecated
struct AVPanScan *pan_scan;
#endif
/**
* reordered opaque 64bit (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
* @deprecated in favor of pkt_pts
*/
int64_t reordered_opaque;
#if FF_API_AVFRAME_LAVC
/**
* @deprecated this field is unused
*/
attribute_deprecated void *hwaccel_picture_private;
attribute_deprecated
struct AVCodecContext *owner;
attribute_deprecated
void *thread_opaque;
/**
* log2 of the size of the block which a single vector in motion_val represents:
* (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)
*/
uint8_t motion_subsample_log2;
#endif
/**
* 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.
*
* 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
* Flags describing additional frame properties.
*
* @{
*/
/**
* The frame data may be corrupted, e.g. due to decoding errors.
*/
#define AV_FRAME_FLAG_CORRUPT (1 << 0)
/**
* @}
*/
/**
* Frame flags, a combination of @ref lavu_frame_flags
*/
int flags;
/**
* MPEG vs JPEG YUV range.
* It must be accessed using av_frame_get_color_range() and
* av_frame_set_color_range().
* - encoding: Set by user
* - decoding: Set by libavcodec
*/
enum AVColorRange color_range;
enum AVColorPrimaries color_primaries;
enum AVColorTransferCharacteristic color_trc;
/**
* YUV colorspace type.
* It must be accessed using av_frame_get_colorspace() and
* av_frame_set_colorspace().
* - 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
* Code outside libavcodec should access this field using:
* av_frame_get_best_effort_timestamp(frame)
* - 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
* Code outside libavcodec should access this field using:
* av_frame_get_pkt_pos(frame)
* - encoding: unused
* - decoding: Read by user.
*/
int64_t pkt_pos;
/**
* duration of the corresponding packet, expressed in
* AVStream->time_base units, 0 if unknown.
* Code outside libavcodec should access this field using:
* av_frame_get_pkt_duration(frame)
* - encoding: unused
* - decoding: Read by user.
*/
int64_t pkt_duration;
/**
* metadata.
* Code outside libavcodec should access this field using:
* av_frame_get_metadata(frame)
* - 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.
* Code outside libavcodec should access this field using:
* av_frame_get_decode_error_flags(frame)
* - 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.
* Code outside libavcodec should access this field using:
* av_frame_get_channels(frame)
* - encoding: unused
* - decoding: Read by user.
*/
int channels;
/**
* 对应packet的尺寸
*/
int pkt_size;
/**
* 成员data指向qscale_table
*/
AVBufferRef *qp_table_buf;
} AVFrame;