On Tue April 9 2013 05:57:40 Tzu-Jung Lee wrote:
> Hi Hans,
>
> > On Mon, Apr 8, 2013 at 10:07 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> >
> > But try the patch below for v4l2-ctl: if you combine streaming with --decoder-cmd
> > then instead of doing a STREAMOFF it will call the decoder command. And the
> > encoder now listens to the EOS event.
> > Note that --en/decoder-cmd=start isn't necessary: STREAMON should call that
> > implicitly as per the spec.
> >
> > Let me know if this works!
>
> The patch works well, thanks!
>
> For trying it out, I need to workaround some frame-based logics.
> (please find the attach patch below)
>
> Quote from the spec:
>
> A read() or VIDIOC_STREAMON call sends an implicit START
> command to the encoder if it has not been started yet.
> After a STOP command, read() calls will read the remaining data
> buffered by the driver. When the buffer is empty, read() will return
> zero and the next read() call will restart the encoder.
>
> A close() or VIDIOC_STREAMOFF call of a streaming file
> descriptor sends an implicit immediate STOP to the encoder, and all
> buffered data is discarded.
>
> So I think I'll make the driver itself stop the codec implicitly in
> the STREAMOFF call as well to conform the spec.
That's correct.
> And then we can change the decoding command line from
>
> v4l2-ctl --stream-poll --stream-out-mmap
> --stream-from=/clips/src.h264 --decoder-cmd=cmd=stop &
> to
> v4l2-ctl --stream-poll --stream-out-mmap --stream-from=/clips/src.h264 &
It's not quite the same thing. STREAMOFF does an immediate stop, discarding
any pending data. --decoder-cmd=cmd=stop will wait for the decoder to finish
decoding any pending data.
I also made a small mistake in my v4l2-ctl patch. This:
if (options[OptDecoderCmd])
doioctl(fd, VIDIOC_DECODER_CMD, &dec_cmd);
else
doioctl(fd, VIDIOC_STREAMOFF, &type);
should be:
if (options[OptDecoderCmd])
doioctl(fd, VIDIOC_DECODER_CMD, &dec_cmd);
doioctl(fd, VIDIOC_STREAMOFF, &type);
since the STOP command doesn't imply a STREAMOFF.
>
> like the encoding command line:
>
> v4l2-ctl --stream-poll --stream-mmap --stream-to=/clips/dst.h264 &
>
> It will be great if we can combine the two command lines into one for
> the transcoding case.
>
> v4l2-ctl --stream-poll --stream-out-mmap
> --stream-from=/clips/src.h264 --stream-mmap
> --stream-to=/clips/dst.h264
That would only be possible for a memory-to-memory device (is that what you have?).
If you have two different video nodes, one for the capture side, one for the output
side, then you need two v4l2-ctl commands, one for each node.
It would certainly be desirable to have mem2mem streaming support in v4l2-ctl.
Patches for that are welcome.
I'm going to commit my patch with the change mentioned above. Please let me know
if you run into problems.
Regards,
Hans
>
>
> p.s. I can help on this for the bitstreaming case, though it will need
> reviewing for not breaking frame-based cases :-)
>
> Thanks.
> Roy
>
> -----------------------
> commit 195e914175b2faf7f2e536cbc32760a18bfa4b28
> Author: Tzu-Jung Lee <tjlee@xxxxxxxxxxxxx>
> Date: Tue Apr 9 11:24:15 2013 +0800
>
> v4l-ctl: add missing declarations
>
> diff --git a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> index 9099f63..df0b2e1 100644
> --- a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> +++ b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> @@ -628,6 +628,8 @@ void streaming_set(int fd)
> unsigned count = 0, last = 0;
> struct timeval tv_last;
> bool eos = false;
> + fd_set read_fds;
> + fd_set exception_fds;
>
> while (!eos) {
> struct v4l2_plane planes[VIDEO_MAX_PLANES];
>
>
> commit 5671c388ecbe448b11f271079dcd88689e753e3b
> Author: Tzu-Jung Lee <tjlee@xxxxxxxxxxxxx>
> Date: Tue Apr 9 11:25:13 2013 +0800
>
> v4l-ctl: tmp hack for straming I/O of bitstreams
>
> diff --git a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> index df0b2e1..5d40810 100644
> --- a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> +++ b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
> @@ -796,10 +796,12 @@ void streaming_set(int fd)
> fmt.type = type;
> doioctl(fd, VIDIOC_G_FMT, &fmt);
>
> +#if 0
> if (!precalculate_bars(fmt.fmt.pix.pixelformat,
> stream_pat % NUM_PATTERNS)) {
> fprintf(stderr, "unsupported pixelformat\n");
> return;
> }
> +#endif
>
> memset(&reqbufs, 0, sizeof(reqbufs));
> reqbufs.count = reqbufs_count;
> @@ -876,6 +878,7 @@ void streaming_set(int fd)
> if (!fin ||
> !fill_buffer_from_file(buffers, buffer_lengths,
> buf.index, num_planes, fin))
> fill_buffer(buffers[i], &fmt.fmt.pix);
> + buf.bytesused = buf.length;
> }
> if (doioctl(fd, VIDIOC_QBUF, &buf))
> return;
>
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