Hi Randy, > From: randy [mailto:lxr1234@xxxxxxxxxxx] > Sent: Friday, January 03, 2014 4:17 PM > > I rewrite my program, it takes the order as below 1.request buffer. > 2.mmap input buffer with OUTPUT > 3.output buffer with CAPTURE. > 4.filled input buffer with the first frame. > 5.enqueue the first frame in the input buffer in OUTPUT side 6.enqueue > the output buffer in CAPTURE side 7.start stream 8.dequeue CAPTURE > buffer and make output buffer pointer to data of it. > 9.get output data from output buffer > /* the buffer get size is 22 below */ > 10.dequeue OUTPUT > /* timed out, it will never end */ > Is there any problem with the order? I don't do any thing > simultaneously below, it seems to difficult to me to understand and not > easy to debug. > I am not sure whether the mmap is correct, but I think it it as I don't > get segment fault. Please have a look at the V4L2_CID_MPEG_VIDEO_HEADER_MODE control. >From your description it seems that it is in its default state - V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE. This means that the header for a newly encoded stream is returned after init. Then in another buffer you will find the encoded picture. So after point 9 please enqueue the CAPTURE buffer again and see what happens. I think that you should get the first frame encoded. You can also try to set the V4L2_CID_MPEG_VIDEO_HEADER_MODE control to V4L2_MPEG_VIDEO_HEADER_MODE_JOINED_WITH_1ST_FRAME and see if it works. (instead of enqueueing the CAPTURE buffer again after receiving the header). In addition I would recommend you to use more than one buffer per queue. > > And the thing in the next is like this I think 11.filled input buffer > with the next frame 12.enqueue the next frame in the input buffer in > OUTPUT side 13.dequeue CAPTURE buffer and make output buffer pointer to > data of it. > 14.dequeue OUTPUT > goto 11 > Is it correct > > I doubt the REAME > 5. Request CAPTURE and OUTPUT buffers. Due to hardware limitations of > MFC on > some platforms it is recommended to use V4L2_MEMORY_MMAP buffers. > 6. Enqueue CAPTURE buffers. > 7. Enqueue OUTPUT buffer with first frame. > 8. Start streaming (VIDIOC_STREAMON) on both ends. > 9. Simultaneously: > I don't need to dequeue the OUTPUT buffer which is with first frame? > - enqueue buffers with next frames, > - dequeue used OUTPUT buffers (blocking operation), > - dequeue buffers with encoded stream (blocking operation), > - enqueue free CAPTURE buffers. > > > Thank you. Best wishes, Kamil -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
