JPEG Codec Decoding does not end/complete

[AWent]

Hey,

I transfered the JPEG_DecodingFromFLASH_DMA example code into program, where I try to decode and display a JPEG image which I receive via SPI (thus, the image data is storred in the Flash as well).

Board: STM32F769I-DISCO

The code is unchanged except of the parameters pointing to the data to be decoded and respectively its length in the JPEG_Decode_DMA function:

JPEG_Decode_DMA(&JPEG_Handle, (uint32_t)frame_buffer, frame_size, JPEG_OUTPUT_DATA_BUFFER);

However, when I wait for the JpegProcessingEnd, the JPEG_OutputHandler never returns a ProcessDoneFlag ('1').

do 
 {
      JpegProcessing_End = JPEG_OutputHandler(&JPEG_Handle);
  }while(JpegProcessing_End == 0);

From Debugging, I know this is because the state

Jpeg_OUT_BufferTab[JPEG_OUT_Read_BufferIndex].State == JPEG_BUFFER_FULL

will never be reaced.

Respectively, the HAL_JPEG_DataReadyCallback will bever be called wich should set the JPEG_BUFFER_FULL state.

And the JPEG_Process will not be executed which would call the Callback, if I got that correctly.

Any idea where and what I need to check to find out why the Decoding won't work?

(I wasn't able to test the original example code, because its too large for my uVision Licence)

[oleksandr.karbivsky]

Hi. Did you transfer example code to your own project? Did you also transfer MDMA configuration?

[AWent]

Hi. Thanks for your hint.

I inserted the JPEG code into my project, yes.

My project is modified SPI_Full_Duplex_Com example. And I took the JPEG_Decoding code from the main, inserted the hal_jpeg driver, the decode_dma module and jpeg_utils plus all header files. Till I got no error messeges anymore.

But I am not quite sure about a MDMA? What is that? I couldn't find anything named MDMA in the JPEG_DecodingFromFLASH_DMA project?

[oleksandr.karbivsky · Accepted solution]

Check that you copy HAL_JPEG_MspInit function to your project (from file stm32h7xx_hal_msp.c in JPEG Example project)

[AWent]

You are right, that is probably the solution! I missed the HAL_JPEG_MspInit function in the stm32f7xx_hal_msp.c, and the Compiler hasn't claimed it, beause its alredy defined as a __WEAK function in the hal_jpeg driver.

Unfortunately, I couldn't test right now, because the project just got to large for the 32K licence, but I will check soon and I am optimistic, that this was the missing point.

[oleksandr.karbivsky]

Good luck)

[AWent]

Thanks a lot again.

Besdies the HAL_JPEG_MspInit function, I also missed to copy some JPEG and DMA IRQHandler in stm32f7xx_it.c.

[AWent]

However, the JPEG_Decode process still does not succeed. It will be aorted by a JPEG_DMAErrorCallback and I cannot figure out why.

To the JPEG_DMAErrorCallback it will be referred as "hjpeg->hdmain->XferErrorCallback" and "hjpeg->hdmaout->XferErrorCallback", but I cannot find the condition for their calls.

Does anyone have a idea or hint?

[oleksandr.karbivsky]

Hi. What is MDMA Error Code Index?

[AWent]

The hjpeg->ErrorCode is 4 (HAL_JPEG_ERROR_DMA, DMA transfer error)

Or is there something more detailed available?