From e284455272857f9c09315d917b3a49640b24de8b Mon Sep 17 00:00:00 2001 From: Robert Swain Date: Wed, 6 Apr 2011 16:11:02 +0200 Subject: [PATCH] docs: Update interlaced video design document The RFF flag is to be reused for buffers in the telecine state to indicate that the buffer contains only unneeded repeated fields that are present in other buffers and as such this buffer can be dropped. --- docs/design/part-interlaced-video.txt | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/docs/design/part-interlaced-video.txt b/docs/design/part-interlaced-video.txt index caef5330e..659314617 100644 --- a/docs/design/part-interlaced-video.txt +++ b/docs/design/part-interlaced-video.txt @@ -77,9 +77,20 @@ Telecine If the caps have interlaced=true and interlacing-method=telecine then the buffers are in some form of telecine state. -The TFF, RFF and ONEFIELD flags have the same semantics as for the plain -interlaced state, however, for the telecine state require one additional flag to -be able to identify progressive buffers. +The TFF and ONEFIELD flags have the same semantics as for the plain interlaced +state. + +GST_VIDEO_BUFFER_RFF in the telecine state indicates that the buffer contains +only repeated fields that are present in other buffers and are as such +unneeded. For example, in a sequence of three telecined frames, we might have: + +AtAb AtBb BtBb + +In this situation, we only need the first and third buffers as the second +buffer contains fields present in the first and third. + +The telecine state require one additional flag to be able to identify +progressive buffers. GST_VIDEO_BUFFER_PROGRESSIVE means that the buffer containing two fields is a progressive frame. The implication is that if this flag is not set, the buffer -- 2.34.1