Extract YUV data from OMX_TI_COLOR_FormatYUV420PackedSemiPlanar on FillBufferDone callback received from OMX

Vinit Adkar

Prodigy 40 points

Hello,

I need a pointer to the UV data in OMX_TI_COLOR_FormatYUV420PackedSemiPlanar decoded buffer

int stride = 4096;
int frame_yoffset = 24;
int frame_xoffset = 32;

uint32_t ybuf_offset = frame_yoffset * stride + frame_xoffset;
uint8_t* p1y = (uint8_t*)srcbuffer + ybuf_offset;

int width = 1280;
int height = 720;

uint32_t UV_offset = frame_xoffset + (frame_yoffset * stride)/2;

I am able to extract Y data correctly.

But i need a pointer to UV data

*pUV = (uint8_t*)srcbuffer + ??

please could you give me sample code or necessary information to extract UV plane data

Thanks

- Vinit

over 13 years ago

0 Vinit Adkar over 13 years ago

Prodigy 40 points

My Video details are

Width = 1280

Height = 720

Parameters returned by OMX :

stride : 4096

Decoded buffer length : 4764928

0 Manuel Contreras over 13 years ago in reply to Vinit Adkar

TI__Genius 10545 points

Next are some post that address similar issue.

http://e2e.ti.com/support/omap/f/849/p/190468/682651.aspx#682651

http://e2e.ti.com/support/omap/f/849/t/193199.aspx

http://e2e.ti.com/support/omap/f/849/p/189036/678397.aspx#678397

0 Vinit Adkar over 13 years ago in reply to Manuel Contreras

Prodigy 40 points

Hi Manuel,

I went through the above posts but still I dont get right result.

In http://e2e.ti.com/support/omap/f/849/p/189036/678397.aspx#678397, it suggests a DebugFrame_Dump structure in which there are two pointers OMX_U32 *y_uv[2];

But in my case i get a pointer to decoded buffer which is of format OMX_TI_COLOR_FormatYUV420PackedSemiPlanar

In Fillbufferdone callback

buffer = message.u.extended_buffer_data.buffer

bufferLength = message.u.extended_buffer_data.range_length (4764928 in my case)

offset = message.u.extended_buffer_data.range_offset

So *pYPlane = buffer + offset;

What is *pUVPlane ??/

Is there anything wrong in my approach.

Thanks,

Vinit

0 Manuel Contreras over 13 years ago in reply to Vinit Adkar

TI__Genius 10545 points

Can you check next post?

http://e2e.ti.com/support/omap/f/849/p/189036/680922.aspx#680922

I remember that there was one post that contained the formula.

0 Shivaraj Shetty over 13 years ago

TI__Prodigy 60 points

Can you try this one?

uint32_t UV_offset = frame_xoffset + (frame_yoffset * stride)/2;

*pUV = (uint8_t*)srcbuffer + (height + 2*frame_yoffset)*stride + UV_offset

Regards,

Shivaraj Shetty

0 Mayank Mangla over 13 years ago in reply to Shivaraj Shetty

TI__Mastermind 24525 points

To summarize:

Color format used is NV12, which is same as YUV420 except that U and V are in the same channel.. pY is Luma channel. pUV is Chroma channel. Chrominance channel has U and V interleaved.

To dump to a file and view it with a standard YUV420 viewer, you need to copy e-interleave U and V into separate planes and write to a file such that Y, U and V are contiguously stored. You also need to take care of stride and offset, This is explained in

http://e2e.ti.com/support/omap/f/849/p/189036/680922.aspx#680922

0 Vinit Adkar over 13 years ago in reply to Mayank Mangla

Prodigy 40 points

uint8_t* p1uv = (uint8_t*)buffer + (height + (9*frame_yoffset/2))*stride + frame_xoffset;

Can you guys explaing why the heigth is offset by (9/2) * stride ??

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Extract YUV data from OMX_TI_COLOR_FormatYUV420PackedSemiPlanar on FillBufferDone callback received from OMX