The expression "len >= 0" is always true since "len"
is an unsigned type. And it is clear that the writers
intention was not to write "len > 0" since we handle
len == 0 in the ensuing "if (len < 3)" conditional
block.
A new FEI based encoder element for h264 is added: vaapih264feienc
FEI is a an extension to VA-API which is providing low level
advanced control over different stages of encoding.
Extending vaapih264enc with fei support is possible, but it will
make the code too much complicated and will be difficult
to debug. So adding the new encoder element, but keeping
the rank as 0 , vaapih264enc will stay as the primary
encoder for normal use cases.
The vaaih264feienc is mainly useful for customers who want to play
with MotionVectors and Macroblock Predictions. Also user can
do one stage of encoding(eg: only the Motion Vector Calculation)
in software and offload trasformation/entroy-coding etc to
Hardware (which is what PAK module is doing) using FEI element.
vaapih264feienc can work in different modes using fei-mode properoty
eg: gst-launch-1.0 videotestsrc ! vaapih264feienc fei-mode=ENC+PAK ! filesink location=sample.264
Important Note: ENC only mode won't produce any encoded data which is expected.
But ENC alwys requires the output of PAK in order to do the inter-prediction
over reconstructed frames.
Similary PAK mode alway requires MV and MBCode as input, so unless there is an
upstream element providing those buffers, PAK only won't work as expected.
In a nutshell, ENC_PAK and the ENC+PAK modes are the only options we can verify
with vaapih264feienc. But ideally, EN+PAK mode verification is enough to make sure
that ENC and PAK are working as expected since ENC+PAK mode always invoke ENC and PAK
separately in vaapih264feienc.
People contributed:
Wang, Yi <yi.a.wang@intel.com>
Leilei <leilei.shang@intel.com>
Zhong, Xiaoxia <xiaoxia.zhong@intel.com>
xiaominc <xiaomin.chen@intel.com>
Li, Jing B <jing.b.li@intel.com>
https://bugzilla.gnome.org/show_bug.cgi?id=785712https://bugzilla.gnome.org/show_bug.cgi?id=784667
Signed-off-by: Sreerenj Balachandran <sreerenj.balachandran@intel.com>
