On 6/9/19 4:38 PM, Maxime Jourdan wrote: > Hello, > > This RFC proposes a new format flag - V4L2_FMT_FLAG_DYN_RESOLUTION - used > to tag coded formats for which the device supports dynamic resolution > switching, via V4L2_EVENT_SOURCE_CHANGE. > This includes the initial "source change" where the device is able to > tell userspace about the coded resolution and the DPB size (which > sometimes translates to V4L2_CID_MIN_BUFFERS_FOR_CAPTURE). Shouldn't the initial source change still be there? The amlogic decoder is capable of determining the resolution of the stream, right? It just can't handle mid-stream changes. Regards, Hans > This flag is mainly aimed at stateful decoder drivers. > > This RFC is motivated by my development on the amlogic video decoder > driver, which does not support dynamic resolution switching for older > coded formats (MPEG 1/2, MPEG 4 part II, H263). It does however support > it for the newer formats (H264, HEVC, VP9). > > The specification regarding stateful video decoders should be amended > to include that, in the absence of this flag for a certain format, > userspace is expected to extract the coded resolution and allocate > a sufficient amount of capture buffers on its own. > I understand that this point may be tricky, since older kernels with > close-to-spec drivers would not have this flag available, yet would > fully support dynamic resolution switching. > However, with the spec not merged in yet, I wanted to have your opinion > on this late addition. > > The RFC patches also adds support for this flag for the 4 following > stateful decoder drivers: > - venus > - s5p-mfc > - mtk-vcodec > - vicodec > > Maxime Jourdan (5): > media: videodev2: add V4L2_FMT_FLAG_DYN_RESOLUTION > media: venus: vdec: flag OUTPUT formats with > V4L2_FMT_FLAG_DYN_RESOLUTION > media: s5p_mfc_dec: flag OUTPUT formats with > V4L2_FMT_FLAG_DYN_RESOLUTION > media: mtk-vcodec: flag OUTPUT formats with > V4L2_FMT_FLAG_DYN_RESOLUTION > media: vicodec: flag vdec/stateful OUTPUT formats with > V4L2_FMT_FLAG_DYN_RESOLUTION > > Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 7 +++++++ > drivers/media/platform/mtk-vcodec/mtk_vcodec_dec.c | 4 ++++ > drivers/media/platform/mtk-vcodec/mtk_vcodec_drv.h | 1 + > drivers/media/platform/qcom/venus/core.h | 1 + > drivers/media/platform/qcom/venus/vdec.c | 11 +++++++++++ > drivers/media/platform/s5p-mfc/s5p_mfc_common.h | 1 + > drivers/media/platform/s5p-mfc/s5p_mfc_dec.c | 13 +++++++++++++ > drivers/media/platform/vicodec/vicodec-core.c | 2 ++ > include/uapi/linux/videodev2.h | 5 +++-- > 9 files changed, 43 insertions(+), 2 deletions(-) >
