buffer

Buffer video frames, and make them available to the filter chain.

This source is mainly intended for a programmatic use, in particular through the interface defined in 'libavfilter/vsrc_buffer.h'.

It accepts the following parameters:

'video_size'

Specify the size (width and height) of the buffered video frames. For the syntax of this option, check the .

'width'

The input video width.

'height'

The input video height.

'pix_fmt'

A string representing the pixel format of the buffered video frames. It may be a number corresponding to a pixel format, or a pixel format name.

'time_base'

Specify the timebase assumed by the timestamps of the buffered frames.

'frame_rate'

Specify the frame rate expected for the video stream.

'pixel_aspect, sar'

The sample (pixel) aspect ratio of the input video.

'sws_param'

Specify the optional parameters to be used for the scale filter which is automatically inserted when an input change is detected in the input size or format.

'hw_frames_ctx'

When using a hardware pixel format, this should be a reference to an AVHWFramesContext describing input frames.

For example: 

buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1

will instruct the source to accept video frames with size 320x240 and with format "yuv410p", assuming 1/24 as the timestamps timebase and square pixels (1:1 sample aspect ratio). Since the pixel format with name "yuv410p" corresponds to the number 6 (check the enum AVPixelFormat definition in 'libavutil/pixfmt.h'), this example corresponds to: 

buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1

Alternatively, the options can be specified as a flat string, but this syntax is deprecated:

width:height:pix_fmt:time_base.num:time_base.den:pixel_aspect.num:pixel_aspect.den[:sws_param]