圖 4-3 展示了 4 攝像頭深度學習 GStreamer 流水線。TI 提供了一套 GStreamer 插件，可將部分媒體處理和深度學習推理負載分流到硬件加速器。這些插件的一些示例包括 tiovxisp、tiovxmultiscaler、tiovxmosaic 和 tidlinferer。圖 4-3 中的流水線包括多路徑 GStreamer 流水線的所有必需插件，用于 4 個攝像頭輸入，每個都帶有媒體預處理、深度學習推理和后處理功能。每個攝像頭路徑的重復插件均在圖形中堆疊在一起，以便于演示。

可用的硬件資源均勻地分布在四個攝像頭路徑中。例如，AM62A 包含兩個圖像多標量：MSC0 和 MSC1。該流水線明確指定了 MSC0 來處理攝像頭 1 和攝像頭 2 路徑，而 MSC1 專用于攝像頭 3 和攝像頭 4。

圖 4-3 AM62A 上四路 CSI IMX219 攝像頭深度學習推理的 GStreamer 流水線

四個攝像頭流水線的輸出通過 tiovxmosaic 插件縮小并連接在一起。輸出顯示在單個屏幕上。圖 4-4 展示了深度學習模型運行對象檢測時四個攝像頭的輸出。每個流水線（攝像頭）以 30FPS 和總計 120FPS 的速度運行。點擊此鏈接可查看展示此演示的錄屏視頻。

圖 4-4 使用 AM62A 且具有圖形性能疊層的四攝像頭物體檢測深度學習推理屏幕截圖

接下來是多攝像頭深度學習用例的完整流水線腳本，如圖 4-3 所示。

gst-launch-1.0 -v \
v4l2src device=/dev/video-imx219-cam0 io-mode=5 ! queue leaky=2 ! video/x-bayer, width=1920, height=1080, format=rggb ! tiovxisp sensor-name=SENSOR_SONY_IMX219_RPI dcc-isp-file=/opt/imaging/imx219/dcc_viss.bin format-msb=7 sink_0::dcc-2a-file=/opt/imaging/imx219/dcc_2a.bin sink_0::device=/dev/v4l-imx219-subdev0 ! video/x-raw, format=NV12 ! \
tiovxmultiscaler target=0 name=split_01 \
split_01. ! queue ! video/x-raw, width=1110, height=690 ! tiovxmultiscaler target=0 ! video/x-raw, width=300, height=300 ! tiovxdlpreproc data-type=3 channel-order=1 tensor-format=rgb out-pool-size=4 ! application/x-tensor-tiovx ! tidlinferer target=1 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 ! post_0.tensor \
split_01. ! queue ! video/x-raw, width=640, height=360 ! post_0.sink \
tidlpostproc name=post_0 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 alpha=0.400000 viz-threshold=0.600000 top-N=5 ! queue ! mosaic_0. \
\
v4l2src device=/dev/video-imx219-cam1 io-mode=5 ! queue leaky=2 ! video/x-bayer, width=1920, height=1080, format=rggb ! tiovxisp sensor-name=SENSOR_SONY_IMX219_RPI dcc-isp-file=/opt/imaging/imx219/dcc_viss.bin format-msb=7 sink_0::dcc-2a-file=/opt/imaging/imx219/dcc_2a.bin sink_0::device=/dev/v4l-imx219-subdev1 ! video/x-raw, format=NV12 ! \
tiovxmultiscaler target=0 name=split_11 \
split_11. ! queue ! video/x-raw, width=1110, height=690 ! tiovxmultiscaler target=0 ! video/x-raw, width=300, height=300 ! tiovxdlpreproc data-type=3 channel-order=1 tensor-format=rgb out-pool-size=4 ! application/x-tensor-tiovx ! tidlinferer target=1 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 ! post_1.tensor \
split_11. ! queue ! video/x-raw, width=640, height=360 ! post_1.sink \
tidlpostproc name=post_1 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 alpha=0.400000 viz-threshold=0.600000 top-N=5 ! queue ! mosaic_0. \
\
v4l2src device=/dev/video-imx219-cam2 io-mode=5 ! queue leaky=2 ! video/x-bayer, width=1920, height=1080, format=rggb ! tiovxisp sensor-name=SENSOR_SONY_IMX219_RPI dcc-isp-file=/opt/imaging/imx219/dcc_viss.bin format-msb=7 sink_0::dcc-2a-file=/opt/imaging/imx219/dcc_2a.bin sink_0::device=/dev/v4l-imx219-subdev2 ! video/x-raw, format=NV12 ! \
tiovxmultiscaler target=1 name=split_21 \
split_21. ! queue ! video/x-raw, width=1110, height=690 ! tiovxmultiscaler target=1 ! video/x-raw, width=300, height=300 ! tiovxdlpreproc data-type=3 channel-order=1 tensor-format=rgb out-pool-size=4 ! application/x-tensor-tiovx ! tidlinferer target=1 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 ! post_2.tensor \
split_21. ! queue ! video/x-raw, width=640, height=360 ! post_2.sink \
tidlpostproc name=post_2 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 alpha=0.400000 viz-threshold=0.600000 top-N=5 ! queue ! mosaic_0. \
\
v4l2src device=/dev/video-imx219-cam3 io-mode=5 ! queue leaky=2 ! video/x-bayer, width=1920, height=1080, format=rggb ! tiovxisp sensor-name=SENSOR_SONY_IMX219_RPI dcc-isp-file=/opt/imaging/imx219/dcc_viss.bin format-msb=7 sink_0::dcc-2a-file=/opt/imaging/imx219/dcc_2a.bin sink_0::device=/dev/v4l-imx219-subdev3 ! video/x-raw, format=NV12 ! \
tiovxmultiscaler target=1 name=split_31 \
split_31. ! queue ! video/x-raw, width=1110, height=690 ! tiovxmultiscaler target=1 ! video/x-raw, width=300, height=300 ! tiovxdlpreproc data-type=3 channel-order=1 tensor-format=rgb out-pool-size=4 ! application/x-tensor-tiovx ! tidlinferer target=1 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 ! post_3.tensor \
split_31. ! queue ! video/x-raw, width=640, height=360 ! post_3.sink \
tidlpostproc name=post_3 model=/opt/model_zoo/TFL-OD-2000-ssd-mobV1-coco-mlperf-300x300 alpha=0.400000 viz-threshold=0.600000 top-N=5 ! queue ! mosaic_0. \
\
tiovxmosaic src::pool-size=3 name=mosaic_0 \
sink_0::startx="<320>"  sink_0::starty="<180>"  sink_0::widths="<640>"   sink_0::heights="<360>"  \
sink_1::startx="<960>"  sink_1::starty="<180>"  sink_1::widths="<640>"   sink_1::heights="<360>"  \
sink_2::startx="<320>"  sink_2::starty="<560>"  sink_2::widths="<640>"   sink_2::heights="<360>"  \
sink_3::startx="<960>"  sink_3::starty="<560>"  sink_3::widths="<640>"   sink_3::heights="<360>"  \
! video/x-raw,format=NV12, width=1920, height=1080 ! queue ! tiperfoverlay title="AM62A: Quad Camera Object Detection" ! kmssink sync=false driver-name=tidss force-modesetting=true