tree a20054e78d1fc8ac72ed7b495c1058f48a865d61
parent 59a08120c27a72bc44a9d7999ebcb82701e9f0d2
author Yaowu Xu <yaowu@google.com> 1565126477 -0700
committer Yaowu Xu <yaowu@google.com> 1565278846 +0000

Add a control to force video mode

This commit adds a control to force video mode in the encoder. When
the encoder is forced in video mode, a single input frame is coded
as video, otherwise encoder codes a single input frame as still
picture using reduced header.

Currently by default, force video mode is on in the library and
aomenc, i.e. if there is only one input frame, encoder will use
video mode to encode the single frame. To force video mode off
and enable encoding of a single video frame using reduced still
picture header, one can pass
  --force-video-mode=0 to aomenc.

Note: even with --force-video-mode=0, input sequence with at least
2 video frames, encoder is operating as if force-video-mode is on.
The only combination producing still picture coded with reduced
header is "--force-video-mode=0 --limit=1"

BUG=aomedia:2425

Change-Id: I5eb2f437ed52cc675ab9549aecc28a8e78b0c325