Le mardi 11 juin 2019 à 20:58 -0400, Nicolas Dufresne a écrit : > Le mardi 11 juin 2019 à 10:52 +0200, Philipp Zabel a écrit : > > On Wed, 2019-06-05 at 15:39 +0200, Hans Verkuil wrote: > > > Hi Maxime, > > > > > > I am wondering if this flag shouldn't be inverted: you set > > > V4L2_FMT_FLAG_DYN_RESOLUTION if dynamic resolution is supported, > > > otherwise it isn't. > > > > > > Can all the existing mainlined codec drivers handle midstream > > > resolution changes? > > > > > > s5p-mfc, venus and mediatek can, but I see no SOURCE_CHANGE event in > > > the coda drivers, so I suspect that that can't handle this. > > > > > > Philipp, what is the status of the coda driver for dynamic resolution > > > changes? > > > > FTR, to my knowledge there is no dynamic resolution change support in > > the firmware, as there is no signal (interrupt nor picture run return > > value) to indicate that different headers were parsed. > > > > I am planning to add the initial source change event required by the > > current decoder API documentation, but I am afraid there will be no > > support for source changes due to mid-stream resolution changes due to > > firmware limitations. > > I'm far from familiar with this IP, but at least on CODA988, I can read > from the manual that the workflow is to first guess the allocation, and > if you guess it wrong, an error is returned. What seems to match the > SOURCE_CHANGE event in that version would be in the picture status > register, the bit 20, which is documented as triggered if the stream > requires bigger buffers sizes, or more buffers. After fixing that, you > should, if I read correctly, retry. > > It does not notify if the buffers are too large, but you can detect, > since there is register with the output stream information. This > basically means that for V4L2 restriction, you'd have to bounce the > buffers on frame size boundary or something like thisé > > This workflow is very similar to how OMX works, but V4L2 is even less > flexible on allocation vs format, forcing more re-allocation. Oh, actually, you already bounce the buffers through the color converter, so I guess this can all be hidden internally. > > > regards > > Philipp
