AVFrame is an abstraction for reference-counted raw multimedia data. More...

Files

file  frame.h
 reference-counted frame API
 

Data Structures

struct  AVFrameSideData
 
struct  AVFrame
 This structure describes decoded (raw) audio or video data. More...
 

Enumerations

enum  AVFrameSideDataType {
  AV_FRAME_DATA_PANSCAN, AV_FRAME_DATA_A53_CC, AV_FRAME_DATA_STEREO3D, AV_FRAME_DATA_MATRIXENCODING,
  AV_FRAME_DATA_DOWNMIX_INFO, AV_FRAME_DATA_REPLAYGAIN, AV_FRAME_DATA_DISPLAYMATRIX, AV_FRAME_DATA_AFD,
  AV_FRAME_DATA_AUDIO_SERVICE_TYPE, AV_FRAME_DATA_SPHERICAL
}
 
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
}
 
enum  { AV_FRAME_CROP_UNALIGNED = 1 << 0 }
 Flags for frame cropping. More...
 

Functions

AVFrameav_frame_alloc (void)
 Allocate an AVFrame and set its fields to default values. More...
 
void av_frame_free (AVFrame **frame)
 Free the frame and any dynamically allocated objects in it, e.g. More...
 
int av_frame_ref (AVFrame *dst, const AVFrame *src)
 Set up a new reference to the data described by the source frame. More...
 
AVFrameav_frame_clone (const AVFrame *src)
 Create a new frame that references the same data as src. More...
 
void av_frame_unref (AVFrame *frame)
 Unreference all the buffers referenced by frame and reset the frame fields. More...
 
void av_frame_move_ref (AVFrame *dst, AVFrame *src)
 Move everything contained in src to dst and reset src. More...
 
int av_frame_get_buffer (AVFrame *frame, int align)
 Allocate new buffer(s) for audio or video data. More...
 
int av_frame_is_writable (AVFrame *frame)
 Check if the frame data is writable. More...
 
int av_frame_make_writable (AVFrame *frame)
 Ensure that the frame data is writable, avoiding data copy if possible. More...
 
int av_frame_copy (AVFrame *dst, const AVFrame *src)
 Copy the frame data from src to dst. More...
 
int av_frame_copy_props (AVFrame *dst, const AVFrame *src)
 Copy only "metadata" fields from src to dst. More...
 
AVBufferRefav_frame_get_plane_buffer (AVFrame *frame, int plane)
 Get the buffer reference a given data plane is stored in. More...
 
AVFrameSideDataav_frame_new_side_data (AVFrame *frame, enum AVFrameSideDataType type, int size)
 Add a new side data to a frame. More...
 
AVFrameSideDataav_frame_get_side_data (const AVFrame *frame, enum AVFrameSideDataType type)
 
void av_frame_remove_side_data (AVFrame *frame, enum AVFrameSideDataType type)
 If side data of the supplied type exists in the frame, free it and remove it from the frame. More...
 
int av_frame_apply_cropping (AVFrame *frame, int flags)
 Crop the given video AVFrame according to its crop_left/crop_top/crop_right/ crop_bottom fields. More...
 

Detailed Description

AVFrame is an abstraction for reference-counted raw multimedia data.

Enumeration Type Documentation

◆ AVFrameSideDataType

Enumerator
AV_FRAME_DATA_PANSCAN 

The data is the AVPanScan struct defined in libavcodec.

AV_FRAME_DATA_A53_CC 

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_STEREO3D 

Stereoscopic 3d metadata.

The data is the AVStereo3D struct defined in libavutil/stereo3d.h.

AV_FRAME_DATA_MATRIXENCODING 

The data is the AVMatrixEncoding enum defined in libavutil/channel_layout.h.

AV_FRAME_DATA_DOWNMIX_INFO 

Metadata relevant to a downmix procedure.

The data is the AVDownmixInfo struct defined in libavutil/downmix_info.h.

AV_FRAME_DATA_REPLAYGAIN 

ReplayGain information in the form of the AVReplayGain struct.

AV_FRAME_DATA_DISPLAYMATRIX 

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_AFD 

Active Format Description data consisting of a single byte as specified in ETSI TS 101 154 using enum AVActiveFormatDescription.

AV_FRAME_DATA_AUDIO_SERVICE_TYPE 

This side data must be associated with an audio frame and corresponds to enum AVAudioServiceType defined in avcodec.h.

AV_FRAME_DATA_SPHERICAL 

The data represents the AVSphericalMapping structure defined in libavutil/spherical.h.

Definition at line 48 of file frame.h.

◆ AVActiveFormatDescription

Enumerator
AV_AFD_SAME 
AV_AFD_4_3 
AV_AFD_16_9 
AV_AFD_14_9 
AV_AFD_4_3_SP_14_9 
AV_AFD_16_9_SP_14_9 
AV_AFD_SP_4_3 

Definition at line 104 of file frame.h.

◆ anonymous enum

anonymous enum

Flags for frame cropping.

Enumerator
AV_FRAME_CROP_UNALIGNED 

Apply the maximum possible cropping, even if it requires setting the AVFrame.data[] entries to unaligned pointers.

Passing unaligned data to Libav API is generally not allowed, and causes undefined behavior (such as crashes). You can pass unaligned data only to Libav APIs that are explicitly documented to accept it. Use this flag only if you absolutely know what you are doing.

Definition at line 586 of file frame.h.

Function Documentation

◆ av_frame_alloc()

AVFrame* av_frame_alloc ( void  )

Allocate an AVFrame and set its fields to default values.

The resulting struct must be freed using av_frame_free().

Returns
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.
Examples:
decode_audio.c, decode_video.c, encode_audio.c, encode_video.c, filter_audio.c, output.c, and transcode_aac.c.

Referenced by alloc_audio_frame(), alloc_picture(), init_input_frame(), init_output_frame(), and main().

◆ av_frame_free()

void av_frame_free ( AVFrame **  frame)

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.

Parameters
frameframe to be freed. The pointer will be set to NULL.
Examples:
decode_audio.c, decode_video.c, encode_audio.c, encode_video.c, filter_audio.c, output.c, and transcode_aac.c.

Referenced by close_stream(), init_output_frame(), load_encode_and_write(), main(), and read_decode_convert_and_store().

◆ av_frame_ref()

int av_frame_ref ( AVFrame dst,
const AVFrame src 
)

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.
Returns
0 on success, a negative AVERROR on error

◆ av_frame_clone()

AVFrame* av_frame_clone ( 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().

Returns
newly created AVFrame on success, NULL on error.

◆ av_frame_unref()

void av_frame_unref ( AVFrame frame)

Unreference all the buffers referenced by frame and reset the frame fields.

Examples:
filter_audio.c.

Referenced by main().

◆ av_frame_move_ref()

void av_frame_move_ref ( AVFrame dst,
AVFrame src 
)

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.

◆ av_frame_get_buffer()

int av_frame_get_buffer ( AVFrame frame,
int  align 
)

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.
Parameters
frameframe in which to store the new buffers.
alignRequired 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.
Returns
0 on success, a negative AVERROR on error.
Examples:
encode_audio.c, encode_video.c, filter_audio.c, output.c, and transcode_aac.c.

Referenced by alloc_audio_frame(), alloc_picture(), get_input(), init_output_frame(), and main().

◆ av_frame_is_writable()

int av_frame_is_writable ( AVFrame frame)

Check if the frame data is writable.

Returns
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 also
av_frame_make_writable(), av_buffer_is_writable()

◆ av_frame_make_writable()

int av_frame_make_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.

Returns
0 on success, a negative AVERROR on error.
See also
av_frame_is_writable(), av_buffer_is_writable(), av_buffer_make_writable()
Examples:
encode_audio.c, encode_video.c, and output.c.

Referenced by fill_yuv_image(), main(), and process_audio_stream().

◆ av_frame_copy()

int av_frame_copy ( AVFrame dst,
const AVFrame src 
)

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.

Returns
>= 0 on success, a negative AVERROR on error.

◆ av_frame_copy_props()

int av_frame_copy_props ( 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.

◆ av_frame_get_plane_buffer()

AVBufferRef* av_frame_get_plane_buffer ( AVFrame frame,
int  plane 
)

Get the buffer reference a given data plane is stored in.

Parameters
planeindex of the data plane of interest in frame->extended_data.
Returns
the buffer reference that contains the plane or NULL if the input frame is not valid.

◆ av_frame_new_side_data()

AVFrameSideData* av_frame_new_side_data ( AVFrame frame,
enum AVFrameSideDataType  type,
int  size 
)

Add a new side data to a frame.

Parameters
framea frame to which the side data should be added
typetype of the added side data
sizesize of the side data
Returns
newly added side data on success, NULL on error

◆ av_frame_get_side_data()

AVFrameSideData* av_frame_get_side_data ( const AVFrame frame,
enum AVFrameSideDataType  type 
)
Returns
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.

◆ av_frame_remove_side_data()

void av_frame_remove_side_data ( AVFrame frame,
enum AVFrameSideDataType  type 
)

If side data of the supplied type exists in the frame, free it and remove it from the frame.

◆ av_frame_apply_cropping()

int av_frame_apply_cropping ( AVFrame frame,
int  flags 
)

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.

Parameters
framethe frame which should be cropped
flagsSome combination of AV_FRAME_CROP_* flags, or 0.
Returns
>= 0 on success, a negative AVERROR on error. If the cropping fields were invalid, AVERROR(ERANGE) is returned, and nothing is changed.