Closed FH0 closed 2 months ago
the second linesize should be 960
.
04-08 03:43:42.924 I videoFrame.planeCount: 2, format: nv12
04-08 03:43:42.924 I i: 0 linesize: 1920 height: 1080
04-08 03:43:42.926 I i: 1 linesize: 1920 height: 1080
If I copy with hard code, it will be OK.
void onFrame(AVFrame *frame) {
if (videoSink == nullptr) {
return;
}
auto fmt = getFormat((AVPixelFormat)frame->format);
QVideoFrame videoFrame({QSize(frame->width, frame->height), fmt});
videoFrame.map(QVideoFrame::WriteOnly);
memcpy(videoFrame.bits(0), frame->data[0], 1920 * 1080);
memcpy(videoFrame.bits(1), frame->data[1], 1920 * 1080 / 2);
videoFrame.unmap(); // TODO use drm prime
emit videoSink->videoFrameChanged(videoFrame);
}
Finally solved by
void onFrame(AVFrame *frame) {
if (videoSink == nullptr) {
return;
}
auto fmt = getFormat((AVPixelFormat)frame->format);
QVideoFrame videoFrame({QSize(frame->width, frame->height), fmt});
videoFrame.map(QVideoFrame::WriteOnly);
for (int i = 0; i < videoFrame.planeCount(); i++) {
memcpy(videoFrame.bits(i), frame->data[i], videoFrame.mappedBytes(i));
}
videoFrame.unmap(); // TODO use drm prime
emit videoSink->videoFrameChanged(videoFrame);
}
But I still don't know how to get buffer from avframe by ffmpeg way.
@FH0
the second linesize should be 960.
It is a semi-planar format, U and V are interleaved, so the 2nd linesize should be 1920.
1.5: bytes_per_pixel of NV12 Y buf: 1920xAlign(1080)x1.5=3133440 (+128=3133568) //<= calc by MPP runtime UV buf: 1920xAlign(540)x1.5=1566720
See this func for more info https://github.com/nyanmisaka/ffmpeg-rockchip/blob/ba84e56c51d9cde1f3b1fead2a21e4d271028709/libavutil/hwcontext_rkmpp.c#L192
I use
av_hwframe_transfer_data
to convertdrm_prime
tonv12
.nv12
has two planes, plane 0 size should be 2073600, plane 1 size should be 1036800, for case 1920x1080. But in factnv12
plane 0 size is 3133568 and plane 1 will causeSegmentation fault
.I use it in my Qt project.