[FFmpeg-user] How to get raw frame data from AVFrame.data[] and AVFrame.linesize[] without specifying the pixel format?

[vivienlwt]

I get the general idea that the frame.data[] is interpreted depending on
which pixel format is the video (RGB or YUV). But is there any general way
to get all the pixel data from the frame? I just want to compute the hash
of the frame data, without interpret it to display the image.

According to AVFrame.h:

uint8_t* AVFrame::data[AV_NUM_DATA_POINTERS]

     pointer to the picture/channel planes.

int AVFrame::linesize[AV_NUM_DATA_POINTERS]

     For video, size in bytes of each picture line.

Does this mean that if I just extract from data[i] for linesize[i] bytes
then I get the full pixel information about the frame?

But according to some rendering code of RGB it seems that for one channel
(channel 0), it contains more data than linesize[0] suggested:

for (int y = 0; y < frameHeight; y++)

        memcpy(img.scanLine(y), frameRGB->data[0] +
y*frameRGB->linesize[0], frameWidth*3);


the code suggests that frameRGB->data[0] actually contains frameHeight *
frameWidth * 3 bytes of data, where frameRGB->linesize[0] = frameWidth*3


So what should be the right way to get all the pixel information from
frame->data[]??

Thanks.




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