Bug 45814

Summary:	[SNB]when encode a 1080P file at 2Mbps, the quality is too bad
Product:	libva	Reporter:	Hai <hai.lan>
Component:	intel	Assignee:	Pengfei <pengfei.qu>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	normal
Priority:	highest	CC:	haihao.xiang, janardanadasa3, seanvk
Version:	unspecified
Hardware:	Other
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Hai 2012-02-08 22:59:32 UTC

Environment:
CPU:SNB
Libva:    (vaapi-ext)baa1c0e18619e23c30e26240a087f6ce95c089df
Intel-driver:(vaapi-ext)7eeb6c9233d1c63d83b578bfca4f292eac8d320c


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Description:Use avcenc to encode a 1080P yuv file to a h.264 file at 2Mbps, the quality is bad.You will find some garbage MB especially for I frames. Besides, the real bitrate is not 2Mbps. It's about 3.9Mbps

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Reproduce step:
1.avcenc 1920 1080 blue_sky_1080p.yuv /tmp/1.264 fb=2000 mode=1
2.use mplayer to play the encoded file, you will find some garbage MB especially for I frames.

Comment 1 ykzhao 2013-11-29 02:53:44 UTC

Will you please try the latest intel-vaapi driver and see whether the issue still exists?

Thanks

Comment 2 janardana 2015-09-27 05:25:35 UTC

Yes. I tried with latest gsteamer-vaapi-master / gsteamer-vaapi-0.6 branch and intel-vaapi driver on intel baytrail (lenevo B50 touch laptop).

Quality becomes bad for below options

vaapiencode_h264 rate-control=cbr bitrate=2048 .

It is very easy to reproduce.

1) Pick up any video file which is 1080 h264 and it has lots of motions (not still picture)
2) Run any gst-launch-1.0 pipeline with |vaapiencode_h264 rate-control=cbr bitrate=2048| option. 


You will surely see it.

Comment 3 Sean V Kelley 2016-11-03 21:15:49 UTC

This is a known limitation of Baytrail CBR.  No plans to change it in that older platform at this time.

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