NVIDIA Tegra
NVIDIA DRIVE OS 5.1 Linux SDK

Developer Guide
5.1.9.0 Release


 
Image OpticalFlow/StereoDisparity (nvmedia_imageofst)
 
Architecture
Command Line Options
Examples
The NvMedia nvmedia_imageofst sample application demonstrates how to use the NvMedia Optical Flow or Stereo Disparity (OFST) APIs to perform motion estimation/stereo matching. The sample uses the NVIDIA® NVENC hardware engine.
nvmedia_imageofst can read YUV files and perform motion estimation/stereo matching on input YUV files. The sample outputs motion vectors for each 4×4 block on the output surface.
Architecture
This figure shows the architecture of the nvmedia_imageofst application.
 
A screenshot of a video game Description generated with high confidence
To run the sample
1. Follow the steps in Building and Running the NvMedia Samples.
2. Launch the application:
$ nvmedia_imageofst -h -v 3
Command Line Options
The sample application command syntax is as follows:
$ nvmedia_imageofst [options]
The command line options are as follows.
String parameters, such as pathnames, have a maximum length of 1024 characters. Restrictions on other types of parameters are noted individually.
Required Command Line Options
Option
Parameter
Description
-f
A pathname
Specifies the full pathname of the input file.
-res
<w>x<h>
Specifies the input surface dimensions, where <w> represents width and <h> represents height. Width and height are separated by a letter ‘x’ with no spaces, for example:
-res 640x480
<w> has a range of [160,3840].
<h> has a range of [64,2160].
-o
A file name
Specifies the full pathname of the output MV file.
Output MV file.
 
The output surface contains 4×4 downsampled MV’s. The size of each MV is:
Optical Flow: 4 bytes (MVx,MVy)
Stereo Disparity: 2 bytes (MVx)
Optional Command Line Options
Option
Parameter
Description
-h
n/a
Displays guidance on using this application.
-v
0: Errors (default)
1: Warnings
2: Info
3: Debug
Logging level.
-crcgen
A pathname of a file to be created with the filetype .crc
Generates CRC values in the specified file.
-crcchk
A pathname of an existing file with the filetype .crc
Checks CRC values against values from the specified file.
-hwid
0 (default)
1
Specifies the nvenc instance ID to use for motion estimation/stereo matching.
-if
0: YV12 (default)
1: IYUV
Input YUV file format.
-frames
An integer
Specifies the number of input frames to be processed
-etype
0: opticalFlow estimation high performance (default)
1: stereoDisparity estimation high performance
2: opticalFlow estimation high quality
3: stereoDisparity estimation high quality
4: opticalFlow estimation ultra-high performance
5: stereoDisparity estimation ultra-high performance
Specifies motion estimation/stereo matching mode.
-ehints
A pathname of an existing file
Specifies the external hints file.
-esegmap
n/a
Enables the segmentation map.
-bit_depth
8: 8 bits (default)
10: 10 bits
12: 12 bits
14: 14 bits
16: 16 bits
Number of bits per components on input surfaces.
-cf_idc
1: 420 (default)
2: 422
3: 444
4: 400
YUV subsampling type of input file.
-forward_ref
n/a
Specifies that the reference frame is forward reference. Used only in optical flow estimation. The default is backward reference.
Examples
These examples demonstrate how to call nvmedia_imageofst to perform various operations.
High performance optical flow estimation using backward reference
$ nvmedia_imageofst -f inputfile -res wxh -o outputfile -etype 0 -frames 20 -v 3
The application performs motion estimation according to the parameters in the command line.
High quality optical flow estimation using forward reference
$ nvmedia_imageofst -f inputfile -res wxh -o outputfile -etype 2 -forward_ref -frames 20 -v 3
The application performs motion estimation according to the parameters in the command line.
High quality Stereo Disparity estimation for YUV subsampling type 444 10-bit input
$ nvmedia_imageofst -f inputfile -res wxh -o outputfile -etype 3 -ehints -bit_depth 10 -cf_idc 3 -frames 20 -v 3
The application performs stereo matching according to the parameters in the command line.
Ultra-high performance Stereo Disparity estimation for YUV subsampling type 422 16-bit input
$ nvmedia_imageofst -f inputfile -res wxh -o outputfile -etype 5 -ehints -bit_depth 16 -cf_idc 2 -frames 20 -v 3
The application performs stereo matching according to the parameters in the command line.
Ultra-high performance Optical Flow estimation with CRC generation
$ nvmedia_imageofst -f inputfile -res wxh -o outputfile -etype 4 -crcgen crcfile -frames 20 -v 3
The application performs motion estimation according to the parameters in the command line.