极限性能
echo performance | tee $(find /sys |grep governor$) # 打开性能模式
export KMSSINK_DISABLE_VSYNC=1 #关闭vsync
echo 400000000 > sys/kernel/debug/clk/aclk_rkvdec/clk_rate # 提高解码频率
echo 0x100 > /sys/module/rk_vcodec/parameters/mpp_dev_debug # 打开mpp解码时间
sink方式
可以通过
gst-inspect-1.0 kmssink
查询sink方式 支持的命令
xvimagesink
xvimagesink 需要有硬件加速
实现多屏：
kmssink
使用AFBC格式播放：
export GST_MPP_VIDEODEC_DEFAULT_ARM_AFBC=1
GST_DEBUG=fpsdisplaysink:5 gst-play-1.0 GUGUDAN-Wonderland.2160p.UHDTV.H265.ts --flags=3 --use-playbin3 --videosink="fpsdisplaysink text-overlay=false video-sink=\"kmssink plane-id=71\" sync=false fps-update-interval=10000 "
注：plane-id使用对应的cluster层
fpsdisplaysink 打开帧率打印
text-overlay=false 关闭字幕
普通播放：
gst-play-1.0 1.mp4 --flags=3 --use-playbin3 --videosink=kmssink plane-id=65
gst-play-1.0 oem/SampleVideo_1280x720_5mb.mp4 --flags=3 --videosink="kmssink connector-id=154"
指定connector-id
GST_DEBUG=kmssink:5 gst-launch-1.0 v4l2src device=/dev/video20 ! queue ! kmssink
实现多屏：
waylandsink
防止丢帧：
配置文件增加 WAYLANDSINK_SYNC_FRAME
export GST_DEBUG=*wayland*:10
gst-play-1.0 /test.mp4 --videosink="waylandsink sync=false" --a udiosink=fakesink 2>&1|grep drop -i 0:00:00.724004250 1064 0x7f8c003060 LOG waylandsink gstwaylandsink.c:918:gst_wayland_sink_show_frame:<waylandsink0> buffer 0x7fa01b9890 dropped (redraw pending)
检查：源文件：buildroot/output/rockchip_px30_64/build/gst1-plugins-bad-1.14.4/ext/wayland# grep WAYLANDSINK_SYNC_FRAME * gstwaylandsink.c: if (g_getenv ("WAYLANDSINK_SYNC_FRAME")) { 库：[root@rk3399:/]# grep WAYLANDSINK_SYNC_FRAME /usr/lib/gstreamer-1.0/libgstwaylandsink.so WAYLANDSINK_SYNC_FRAME
实现多屏：
v4l2src
gst-launch-1.0 -v v4l2src ! 'video/x-raw,format=NV12' ! mpph264enc ! filesink location="bla.h264"
gst-launch-1.0 v4l2src ! video/x-raw,format=NV12,width=1920,height=1080 ! rkximagesink
gst-launch-1.0 v4l2src ! video/x-raw,format=RGB3,width=3840,height=2160 ! rkximagesink
gst-launch-1.0 v4l2src device=/dev/video17 ! video/x-raw,format=RGB3,width=1920, height=1080 ! rkximagesink
gst-launch-1.0 v4l2src device=/dev/video20 ! queue ! kmssink
零零碎碎
videoscale是硬件加速，videocrop是软件。较新的gstreamer-rockchip的解码插件支持硬件crop和缩放，比如：
gst-launch-1.0 videotestsrc ! mpph264enc ! h264parse ! mppvideodec crop-rectangle='<100,100,100,100>' width=400 height=400 ! waylandsink处理顺序是先缩放再裁减
gstreamer里面的crop是可以通过crop meta进行in place处理，即直接传递裁减区域信息给最终sink端，由sink端处理裁减（kmssink的话是设置drm的src显示区域）。但是in place处理也需求videocrop直连sink。此外kmssink也支持直接配置目标显示区域render-rectangle进行硬件缩放，但是会受到高宽比限制。所以也可以：
buildroot更新到：https://github.com/JeffyCN/rockchip_mirrors/commit/e7c6827a78434aac1aadf95d763bfc318c3b8e5c
gst-launch-1.0 filesrc location=/FPS_test_1080p60_L4.2.mkv ! matroskademux ! decodebin ! videocrop top=0 bottom=0 left=0 right=960 ! kmssink render-rectangle='<0,0,1920,1080>' force-aspect-ratio=false
jerkiness一般是指播放抖动（偶尔丢帧），卡顿是laggy，闪烁是blink和flick。
硬件加速也是存在耗时的，如其他issue回复，产生耗时的plugin前后最好是加上缓冲队列queue进行异步
确认硬件加速可以通过log开关：
export GST_DEBUG=videoflip:5,video-converter:5
gst-launch-1.0 ... ! videoscale ! video/x-raw, width=500, height=500 ! ...0:00:02.974151424 13319 0x3f640300 DEBUG video-converter video-converter.c:2862:video_converter_try_rga: converted with RGA
[root@RK356X:/]# GST_DEBUG=mppdec:5 gst-launch-1.0 filesrc location=/test.mp4 ! qtdemux ! h264parse ! mppvideodec crop-rectangle='<0,0,960,1080>' width=3840 height=1080 ! queue ! kmssink 2>&1|grep crop
0:00:01.271583086 778 0x3e9ebde0 DEBUG mppdec gstmppdec.c:688:gst_mpp_dec_get_gst_buffer:<mppvideodec0> cropping <0,0,960,1080> within <0,0,3840,1080>
[root@RK356X:/]# tail -10 /sys/kernel/debug/dri/0/summary
win_id: 3
format: NV12 little-endian (0x3231564e) SDR[0] color_space[0] glb_alpha[0xff
]
rotate: xmirror: 0 ymirror: 0 rotate_90: 0 rotate_270: 0
csc: y2r[1] r2y[0] csc mode[1]
zpos: 3
src: pos[0, 0] rect[960 x 1080] 《--- crop到960
dst: pos[480, 0] rect[960 x 1080]
buf[0]: addr: 0x00000000040b1000 pitch: 3840 offset: 0 《--- 3840
buf[1]: addr: 0x00000000040b1000 pitch: 3840 offset: 4147200
Video Port1: DISABLED
[root@rk3399:/]# GST_DEBUG=mppdec:5 gst-launch-1.0 filesrc location=/test.mp4 !qtdemux ! h264parse ! mppvideodec crop-rectangle='<0,0,960,1080>' width=3840 height=1080 ! queue ! kmssink 2>&1|grep crop
0:00:01.085029657 1428 0x2fd6a40 DEBUG mppdec gstmppdec.c:678:gst_mpp_dec_get_gst_buffer:<mppvideodec0> cropping <0,0,960,1080> within <0,0,3840,1080>
[root@rk3399:/]# cat /sys/kernel/debug/dri/0/summary
VOP [ff900000.vop]: ACTIVE
Connector: HDMI-A
overlay_mode[0] bus_format[100a] output_mode[f] color_space[0]
Display mode: 1920x1080p60
clk[148500] real_clk[148500] type[48] flag[5]
H: 1920 2008 2052 2200
V: 1080 1084 1089 1125
win0-0: ACTIVE
format: XR24 little-endian (0x34325258) SDR[0] color_space[0] 《----- 主图层
csc: y2r[0] r2r[0] r2y[0] csc mode[0]
zpos: 0
src: pos[0x0] rect[1920x1080]
dst: pos[0x0] rect[1920x1080]
buf[0]: addr: 0x0000000008c2f000 pitch: 7680 offset: 0
win1-0: ACTIVE
format: NV12 little-endian (0x3231564e) SDR[0] color_space[0] 《----- 视频图层
csc: y2r[1] r2r[0] r2y[0] csc mode[1]
zpos: 1
src: pos[0x0] rect[960x1080] 《---裁减到960x1080
dst: pos[480x0] rect[960x1080] 《-----显示到480,0
buf[0]: addr: 0x000000007e774000 pitch: 3840 offset: 0 《---- 原图是缩放到3840宽
buf[1]: addr: 0x000000007e774000 pitch: 3840 offset: 4147200
参考文档
参考文档：
博主文章 http://blog.iotwrt.com/media/2017/11/17/gstreamer-study/
官网 https://gstreamer.freedesktop.org/documentation/opengl/?gi-language=c
gstreamer官网教程学习 https://blog.csdn.net/u010168781/article/details/105750991
下载地址 git clone https://gitlab.freedesktop.org/gstreamer/gstreamer.git