An error occurred while running sample_encode with mpeg2 encoding method

./sample_encode mpeg2 -i 720.nv12 -w 1280 -h 720 -o 1.mpeg2

CONFIGURE LOADER: required implementation: hw
CONFIGURE LOADER: required implementation mfxAccelerationMode: MFX_ACCEL_MODE_VIA_VAAPI

[ERROR], sts=MFX_ERR_UNSUPPORTED(-3), AllocFrames, QueryIOSurf (for encoder) failed at /root/Desktop/20241118/oneVPL/tools/legacy/sample_encode/src/pipeline_encode.cpp:1043

[ERROR], sts=MFX_ERR_UNSUPPORTED(-3), ResetMFXComponents, AllocFrames failed at /root/Desktop/20241118/oneVPL/tools/legacy/sample_encode/src/pipeline_encode.cpp:2109

[ERROR], sts=MFX_ERR_UNSUPPORTED(-3), Init, ResetMFXComponents failed at /root/Desktop/20241118/oneVPL/tools/legacy/sample_encode/src/pipeline_encode.cpp:1891

[ERROR], sts=MFX_ERR_UNSUPPORTED(-3), main, pPipeline->Init failed at /root/Desktop/20241118/oneVPL/tools/legacy/sample_encode/src/sample_encode.cpp:1920
Frame number: 0
Encoding fps: -nan

But run with h264 is ok
./sample_encode h264 -i 720.nv12 -w 1280 -h 720 -o 1.h264
CONFIGURE LOADER: required implementation: hw
CONFIGURE LOADER: required implementation mfxAccelerationMode: MFX_ACCEL_MODE_VIA_VAAPI
Loaded Library configuration:
Version: 2.13
ImplName: mfx-gen
Adapter number : 0
Adapter type: integrated
DRMRenderNodeNum: 128
Used implementation number: 0
Loaded modules:
0: /opt/intel/mediasdk/lib/libmfx-gen.so.1.2.13

Encoding Sample Version 2.13.0

Input file format YUV420
Output video AVC
Source picture:
Resolution 1280x720
Crop X,Y,W,H 0,0,1280,720
Destination picture:
Resolution 1280x720
Crop X,Y,W,H 0,0,1280,720
Frame rate 30.00
Bit rate(Kbps) 3231
Gop size 0
Ref dist 4
Ref number 0
Idr Interval 0
Target usage balanced
Memory type system
Media SDK impl hw
Media SDK version 2.13

Processing started
Frame number: 1
Encoding fps: 1140

Processing finished

Reproduce the mpeg2 and h264 commands, then inspect the reported paths in tools/legacy/sample_encode/src/pipeline_encode.cpp at lines 1043, 1891, and 2109, plus sample_encode.cpp at line 1920. Compare the encoder initialization paths and determine why mpeg2 returns MFX_ERR_UNSUPPORTED; the issue is resolved when the cause and supported behavior are established.

Written by the indexing model from the issue text.