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MFX_ERR_UNKNOWN is returned from SyncOperation()


Hello All,

I have implemented an encoding product with Intel Media SDK 2016 R2 and sample codes.
So I have met an encoding problem in a sample code.


[Issue 1]
It is occurred an INIFINITE loop at GetFreeSurface() in sample_utils.cpp with a relatively low frequency
which is located the loop calling at GetFreeSurfaceIndex() and MSDK_SLEEP() alternately.

In this case, I have inserted a work arround as follows;
Add a number of two allocation frames at CEncodingPipeline::AllocFrames() in pipeline_encode.cpp.

nEncSurfNum = EncRequest.NumFrameSuggested;
nEncSurfNum += 2;


And then, I met a different problem as follows;

[Issue 2]
An error MFX_ERR_UNKNOWN is returned from SyncOperation() at CEncTaskPool::SynchronizeFirstTask() in pipeline_encode.cpp.
which is occurred with low frequency same as Issue 1.


How can I resolve the problem with what fix I should make?


Best regards,

Mitsuteru Watanabe

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3 Replies

In addition, I have tested any number of times executing the sample encode with Intel Media SDK 2017 R1, then I have the same result.
In this case, I did not modify the sample codes.

The error messages as follows:

[ERROR], sts=MFX_ERR_UNKNOWN(-1), CEncodingPipeline::GetFreeTask, m_TaskPool.SynchronizeFirstTask failed at src\pipeline_encode.cpp:1445
[ERROR], sts=MFX_ERR_UNKNOWN(-1), CEncodingPipeline::Run, m_pmfxENC->EncodeFrameAsync failed at src\pipeline_encode.cpp:1649
[ERROR], sts=MFX_ERR_UNKNOWN(-1), wmain, pPipeline->Run failed at src\sample_encode.cpp:1027
Encoding Sample Version
Input file format YUV420
Output video AVC 
Source picture:
Resolution 720x480
Crop X,Y,W,H 0,0,720,480
Destination picture:
Resolution 720x480
Crop X,Y,W,H 0,0,720,480
Frame rate 29.97
Bit rate(Kbps) 2395
Gop size 30
Ref dist 0
Ref number 0
Idr Interval 0
Target usage balanced
Memory type system
Media SDK impl sw
Media SDK version 1.19
Processing started
Frame number: 1
Frame number: 100
Frame number: 200
Frame number: 258


 In this case, MFX_ERR_UNKNOWN is returned from SyncOperation() at 136 line in pipeline_encode.cpp

sts = m_pmfxSession->SyncOperation(m_pTasks[m_nTaskBufferStart].EncSyncP, MSDK_WAIT_INTERVAL);


However I can not the reason why the error code is returned in this situation.
Does anyone have some information as same as this issue?

Best regards,

Mitsuteru Watanabe

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Hello, Mitsuteru.

Could you provide full command line an full output log (the log you'v posted in previous message seems to be partial) ? Also, please write what version of samples you're using (what is samples' package name).

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Hi Fedor,

The frequency of occurrence of this bug is very low.

Sometimes occurring within 1 hour, sometimes it doesn't occur for more than 24 hours.

Full command line:
    sample_encode.exe -sw -b 2395 -tff -f 29.97 -g 30 -idr_interval 0 -w 720 -h 480 -CodecProfile 100 -CodecLevel 32 -i city_720_480_2997fps.yuv -o city_720_480_2997fps.264 > stdout_stderr_%LOOP_CNT%.txt 2>&1

%LOOP_CNT% is loop counter incremented in bat file.

Full output log:
    The log I have posted is full output log containing messages from stdout and stderr.

Version of samples:
    IntelMSDK Samples R2 for Intel(R) Media Server Studio 2017
    It was downloaded from

About intput movie file:
  Download city_4cif_30fps.y4m from
  Convert file format y4m to yuv.
  Convert width and height 704x576 to 720x480.


  Best regards,
  Mitsuteru Watanabe

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