returns GST_FLOW_ERROR if NULL.
When pad is flushing this function returns GST_FLOW_FLUSHING
immediately and buffer is NULL.
Calls the getrange function of pad, see GstPadGetRangeFunction for a
description of a getrange function. If pad has no getrange function
installed (see gst_pad_set_getrange_function()) this function returns
GST_FLOW_NOT_SUPPORTED.
If buffer points to a variable holding NULL, a valid new GstBuffer will be
placed in buffer when this function returns GST_FLOW_OK. The new buffer
must be freed with gst_buffer_unref() after usage.
When buffer points to a variable that points to a valid GstBuffer, the
buffer will be filled with the result data when this function returns
GST_FLOW_OK. If the provided buffer is larger than size, only
size bytes will be filled in the result buffer and its size will be updated
accordingly.
Note that less than size bytes can be returned in buffer when, for example,
an EOS condition is near or when buffer is not large enough to hold size
bytes. The caller should check the result buffer size to get the result size.
When this function returns any other result value than GST_FLOW_OK, buffer
will be unchanged.
This is a lowlevel function. Usualy gst_pad_pull_range() is used.
returns GST_FLOW_ERROR if NULL. When pad is flushing this function returns GST_FLOW_FLUSHING immediately and buffer is NULL. Calls the getrange function of pad, see GstPadGetRangeFunction for a description of a getrange function. If pad has no getrange function installed (see gst_pad_set_getrange_function()) this function returns GST_FLOW_NOT_SUPPORTED. If buffer points to a variable holding NULL, a valid new GstBuffer will be placed in buffer when this function returns GST_FLOW_OK. The new buffer must be freed with gst_buffer_unref() after usage. When buffer points to a variable that points to a valid GstBuffer, the buffer will be filled with the result data when this function returns GST_FLOW_OK. If the provided buffer is larger than size, only size bytes will be filled in the result buffer and its size will be updated accordingly. Note that less than size bytes can be returned in buffer when, for example, an EOS condition is near or when buffer is not large enough to hold size bytes. The caller should check the result buffer size to get the result size. When this function returns any other result value than GST_FLOW_OK, buffer will be unchanged. This is a lowlevel function. Usualy gst_pad_pull_range() is used.