sample_pym User Guide

Function Overview

sample_pym reads a YUV file into memory allocated by hbm and passes it to the PYM. The PYM processes the data in pyramid layers and finally dumps the processed YUV data into the file system.

Code Location and Directory Structure

• Code location: /app/multimedia_samples/sample_pym
• Directory structure:

sample_pym/
├── Makefile
└── sample_pym.c

Compilation

Run the make command in the source code path to complete the compilation:

cd /app/multimedia_samples/sample_pym
make

Running

How to Run the Program

Execute the program directly with ./sample_pym to get help information:

Program Parameter Options

./sample_pym
Usage: sample_pym [OPTIONS]
Options:
-i, --input_file FILE   Specify the input file
-w, --input_width WIDTH Specify the input width
-h, --input_height HEIGHT       Specify the input height
-f, --feedback                  Specify feedback mode
-V, --verbose           Enable verbose mode

• i: Specify the input YUV file. The test program uses a file in NV12 format as input.
• w: Width of the input YUV image.
• h: Height of the input YUV image.
• f: Specify the PYM operation mode. The default mode is Vflow.

Running Effect

Take a YUV image with an input resolution of 1920 x 1080 as an example: run ./sample_pym -i /app/res/assets/nv12_1920x1080.yuv -w 1920 -h 1080.

Feed a YUV image into the PYM, initialize 6 channels, perform scaling operations at ratios of 1, 1/2, 1/4, 1/8, 1/16, and 1/32 respectively, and save the processed images as YUV images:

• Channel 0 outputs the original resolution of the input image: 1920 x 1080.
• Channel 1 outputs an image scaled down by a factor of 2 in both width and height: 960 x 540.
• Channel 2 outputs an image scaled down by a factor of 4 in both width and height: 480 x 270.
• Channel 3 outputs an image scaled down by a factor of 8 in both width and height: 240 x 134.
• Channel 4 outputs an image scaled down by a factor of 16 in both width and height: 120 x 66.
• Channel 5 outputs an image scaled down by a factor of 32 in both width and height: 60 x 32.

The output log is as follows:

pym vnode work mode: vflow
Using input file:/app/res/assets/nv12_1920x1080.yuv, input:1920x1080
(read_yuvv_nv12_file):file read(/app/res/assets/nv12_1920x1080.yuv), y-size(2073600)

pym config:
        ichn input width = 1920, height = 1080
        ochn[0] ratio= 1, width = 1920, height = 1080 wstride=1920 vstride=1080 out[1920*1080]
        ochn[1] ratio= 2, width = 960, height = 540 wstride=960 vstride=540 out[960*540]
        ochn[2] ratio= 4, width = 480, height = 270 wstride=480 vstride=270 out[480*270]
        ochn[3] ratio= 8, width = 240, height = 134 wstride=240 vstride=134 out[240*134]
        ochn[4] ratio= 16, width = 120, height = 66 wstride=128 vstride=66 out[120*66]
        ochn[5] ratio= 32, width = 60, height = 32 wstride=64 vstride=32 out[60*32]

Note:

1. The width output by the PYM module is aligned to 16 bytes. When viewing the image, pay attention to cases where the width and wstride parameters differ.