f_write dropped 3 bytes

mthanh2602 · ‎2018-12-02

Hello, sorry for posting this post again.

I have a problem with my code. I'm trying to write a program to take picture from camera and save it as motion jpeg video (MJPEG) in to USB. I build already the header and the structure of MJPEG file but it's really weird when I try to run that avi file. Also with the source code was provided by STM, I finished to create the JPEG file.

I had checked and found out that the output data of frames and the idx1 is written by f_write was incorrect. Sometime 2 byte were written again. Someone told me maybe this problems is [3 bytes were dropped].

The header data I wrote to the begin of file is always right, but the data that I wrote to frame place and idx1 place usually has problem.

I want to write data like this below

01 02 03 04 05

but the output was like this

01 02 03 04 05

*01 02 01 02* 03

04 05 01 02 03

This link below simply show some information about MJPEG construction https://blog.goo.ne.jp/sirius506/e/442f430a1531c018a32471f1ecd4ae77

This is the f_write function I used

UINT frame_count = 0;
f_write (&JPEG_File, Frame, sizeof(Frame), &frame_count);
 
FRESULT f_write (
FIL* fp,            /* Pointer to the file object */
const void* buff,   /* Pointer to the data to be written */
UINT btw,           /* Number of bytes to write */
UINT* bw            /* Pointer to number of bytes written */
)
 
//USB init
 USBH_StatusTypeDef USBH_LL_Init(USBH_HandleTypeDef *phost)
{
#ifdef USE_USB_HS  
  /* Set the LL driver parameters */
  hhcd.Instance = USB_OTG_HS;
  hhcd.Init.Host_channels = 11; 
  hhcd.Init.dma_enable = 1;
  hhcd.Init.low_power_enable = 0;
#ifdef USE_USB_HS_IN_FS
  hhcd.Init.phy_itface = HCD_PHY_EMBEDDED; //This is not
#else  
  hhcd.Init.phy_itface = HCD_PHY_ULPI; //This ok
#endif  
  hhcd.Init.Sof_enable = 0;
  hhcd.Init.speed = HCD_SPEED_HIGH;
  hhcd.Init.use_external_vbus = 1;  
  /* Link the driver to the stack */
  hhcd.pData = phost;
  phost->pData = &hhcd;
  /* Initialize the LL driver */
  HAL_HCD_Init(&hhcd);
 
#endif /*USE_USB_HS*/ 
  USBH_LL_SetTimer(phost, HAL_HCD_GetCurrentFrame(&hhcd));
 
  return USBH_OK;
}

Please see the attached picture for more detail. I opened my MJPEG (avi) file by RIFF pad and it show me that the header was written into this output file was completely okay.

Anybody have experience about this? I am very appreciate with any advise.

Sorry for my English. Thank so much.