于 2014年01月02日 20:59, Kamil Debski 写道: > Hi, > >> From: lxr1234 [mailto:lxr1234@xxxxxxxxxxx] >> Sent: Thursday, January 02, 2014 1:57 PM >> To: Kamil Debski >> Subject: RE: using MFC memory to memery encoder, start stream and queue >> order problem >> >> >> >> Kamil Debski <k.debski@xxxxxxxxxxx>写到： >>> Hi Randy, >>> >>>> From: randy [mailto:lxr1234@xxxxxxxxxxx] >>>> Sent: Thursday, January 02, 2014 12:35 PM >>>> Hello >>>> >>>> I have follow the README of the v4l2-mfc-encoder from the >>>> http://git.infradead.org/users/kmpark/public-apps >>>> it seems that I can use the mfc encoder in exynos4412(using 3.5 >>> kernel >>>> from manufacturer). >>> >>> So it is not the mainline kernel. Could you give a link to this >> kernel? >>> I have doubts that this kernel is using the open source driver. The >>> driver present in that kernel could be a significantly modified >> driver. >>> >> Sorry, It doesn't in a git repo I will update,it later, the kernel is >> from friendlyarm, I see driver source in kernel. >>>> But I have a problem with the contain of the README and I can't get >>> the >>>> key frame(the I-frame in H.264). It said that "6. Enqueue CAPTURE >>>> buffers. >>>> 7. Enqueue OUTPUT buffer with first frame. >>>> 8. Start streaming (VIDIOC_STREAMON) on both ends." >>>> so I shall enqueue buffer before start stream, to enqueue a buffer, >> I >>>> need to dequeue first, but without start stream, it will failed in >>> both >>>> side. >>> >>> I think I don't understand this. You should enqueue the buffers and >>> then >>> start streaming. I think dequeueing is not mentioned here. First >>> enqueue >>> then dequeue. >> Without dequeue, hwo to get a buffer to fill data(first raw video)? >> And what shall enqueue in CAPTURE. >> Is there a guide fo usibg memory to memory driver? > > After doing a VIDIOC_REQBUFS you should do a VIDIOC_QUERYBUF call > to get the buffers. After that you can enqueue them. > > I suggest that you first run decoding. v4l2-mfc-example from public-apps. > This way you could see how the V4L2 framework works. > I have another problem with this, if I only request one buffer from driver(index=0 in v4l2_buffer and only call VIDIOC_QUERYBUF) in both side(OUTPUT and CAPTURE). then "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: - enqueue buffers with next frames," I only have one buffer in OUTPUT, shall I do the next step first? " - dequeue used OUTPUT buffers (blocking operation), - dequeue buffers with encoded stream (blocking operation), - enqueue free CAPTURE buffers. " I have used do the thing below after VIDIOC_QUERYBUF in both sides, input_buffer.plane[0].data = mmap(NULL, buffer.m.planes[0].length, PROT_READ | PROT_WRITE,MAP_SHARED, ctx->fd, buffer.m.planes[0].m.mem_offset); input_buffer.plane[1].data = mmap(NULL, buffer.m.planes[1].length, PROT_READ | PROT_WRITE,MAP_SHARED, ctx->fd, buffer.m.planes[1].m.mem_offset); so for the the OUTPUT, I shall copy the raw video into the the input_buffer.plane[0].data and input_buffer.plane[1].data for different planes and then enqueue it? >>>> In this way I start OUTPUT(input raw video) stream first then >> dequeue >>>> and enqueue the first frame, then I start the CAPTURE(output encoded >>>> video) frame, dequeue CAPTURE to get a buffer, get the data from >>> buffer >>>> then enqueue the buffer. The first frame of CAPTURE is always a >>>> 22 bytes >>>> frame(I don't know whether they are the same data all the time, but >>>> size is the same from m.planes[0].bytesused), but it seems not a key >>>> frame. >>>> >>>> What is the problem, and how to solve it. >>>> >>>> P.S I don't test the Linux 3.13-rc4, as the driver is not ready for >>>> encoder before. >>>> >>>> Thank you >>> >>> Best wishes, >> Thank you >> -- >> lxr1234 > > Best wishes, > Kamil > > > Thank you ayaka -- 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
