Maximum size of a JPEG frame buffer

[informx]

Hi,

what is the maximum size of a buffer containing one JPEG frame (any quality and with NO bayer data inside)? If possible I would like know/calculate this information "statically", not at run-time by configuring and querying the encoder component with MMAL.

[jamesh]

Not sure. The same GPU is used on the Nokia 808, which can handle a 38MP image and save it to JPEG. Clearly the JPEG buffer will be smaller than 38MP, but still much larger than most cameras out there require.

So 'quite big' would be the cop out answer.

[6by9]

There is no right answer as there are too many variables.
A worst case guesstimate (and what the MMAL component currently works with) would be width*height bytes, but I'd be surprised if you ever really exceeded half of that. The JPEG codec works in a linear manner over the image, so it doesn't care and will just create multiple buffers to carry the required data.