From: Tomasz Figa <tfiga@chromium.org>
To: Michael Tretter <m.tretter@pengutronix.de>
Cc: "Linux Media Mailing List" <linux-media@vger.kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Hans Verkuil" <hverkuil@xs4all.nl>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Pawel Osciak" <posciak@chromium.org>,
"Alexandre Courbot" <acourbot@chromium.org>,
"Kamil Debski" <kamil@wypas.org>,
"Andrzej Hajda" <a.hajda@samsung.com>,
"Kyungmin Park" <kyungmin.park@samsung.com>,
"Jeongtae Park" <jtp.park@samsung.com>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
"Tiffany Lin (林慧珊)" <tiffany.lin@mediatek.com>,
"Andrew-CT Chen (陳智迪)" <andrew-ct.chen@mediatek.com>,
"Stanimir Varbanov" <stanimir.varbanov@linaro.org>,
"Todor Tomov" <todor.tomov@linaro.org>,
"Nicolas Dufresne" <nicolas@ndufresne.ca>,
"Paul Kocialkowski" <paul.kocialkowski@bootlin.com>,
"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
dave.stevenson@raspberrypi.org,
"Ezequiel Garcia" <ezequiel@collabora.com>,
"Maxime Jourdan" <maxi.jourdan@wanadoo.fr>
Subject: Re: [PATCH v3 2/2] media: docs-rst: Document memory-to-memory video encoder interface
Date: Thu, 16 May 2019 17:48:07 +0900 [thread overview]
Message-ID: <CAAFQd5BNvip1SGA21_C+ogB276jog2CupkKV3TZ_FUO90y0c=Q@mail.gmail.com> (raw)
In-Reply-To: <20190516103715.283face8@litschi.hi.pengutronix.de>
On Thu, May 16, 2019 at 5:37 PM Michael Tretter
<m.tretter@pengutronix.de> wrote:
>
> On Tue, 14 May 2019 17:12:04 +0900, Tomasz Figa wrote:
> > Hi Michael,
> >
> > On Tue, Apr 30, 2019 at 07:34:12PM +0200, Michael Tretter wrote:
> > > On Thu, 24 Jan 2019 19:04:19 +0900, Tomasz Figa wrote:
> >
> > [snip]
> >
> > > > +State machine
> > > > +=============
> > > > +
> > > > +.. kernel-render:: DOT
> > > > + :alt: DOT digraph of encoder state machine
> > > > + :caption: Encoder state machine
> > > > +
> > > > + digraph encoder_state_machine {
> > > > + node [shape = doublecircle, label="Encoding"] Encoding;
> > > > +
> > > > + node [shape = circle, label="Initialization"] Initialization;
> > > > + node [shape = circle, label="Stopped"] Stopped;
> > > > + node [shape = circle, label="Drain"] Drain;
> > > > + node [shape = circle, label="Reset"] Reset;
> > > > +
> > > > + node [shape = point]; qi
> > > > + qi -> Initialization [ label = "open()" ];
> > > > +
> > > > + Initialization -> Encoding [ label = "Both queues streaming" ];
> > > > +
> > > > + Encoding -> Drain [ label = "V4L2_DEC_CMD_STOP" ];
> > > > + Encoding -> Reset [ label = "VIDIOC_STREAMOFF(CAPTURE)" ];
> > > > + Encoding -> Stopped [ label = "VIDIOC_STREAMOFF(OUTPUT)" ];
> > > > + Encoding -> Encoding;
> > > > +
> > > > + Drain -> Stopped [ label = "All CAPTURE\nbuffers dequeued\nor\nVIDIOC_STREAMOFF(CAPTURE)" ];
> > >
> > > Shouldn't this be
> > >
> > > Drain -> Stopped [ label = "All OUTPUT\nbuffers dequeued\nor\nVIDIOC_STREAMOFF(OUTPUT)" ];
> > >
> > > ? While draining, the encoder continues encoding until all source
> > > buffers, i.e., buffers in the OUTPUT queue, are encoded or STREAMOFF
> > > happens on the OUTPUT queue. At the same time, the client continues to
> > > queue and dequeue buffers on the CAPTURE queue and there might be
> > > buffers queued on the CAPTURE queue even if the driver returned the
> > > buffer with the FLAG_LAST set and returns -EPIPE on further DQBUF
> > > requests.
> > >
> >
> > The STREAMOFF should be on OUTPUT indeed, because that immediately
> > removes any OUTPUT buffers from the queue, so there is nothing to be
> > encoded to wait for anymore.
> >
> > The "All OUTPUT buffers dequeued" part is correct, though. The last
I just realized that I made a typo here, sorry. It obviously should be
"All CAPTURE buffers dequeued", as per the existing spec draft and
rest of the sentence. Fortunately you seem to have figured that out.
:)
> > OUTPUT buffer in the flush sequence is considered encoded after the
> > application dequeues the corresponding CAPTURE buffer is dequeued and
> > that buffer is marked with the V4L2_BUF_FLAG_LAST flag.
>
> I understand. As the application continues to queue and dequeue buffers
> on the CAPTURE queue until it received the last CAPTURE buffer and cannot
> dequeue further CAPTURE buffers, "All CAPTURE buffers dequeued" is
> correct. Thanks for the clarification.
>
> Michael
>
> >
> > Best regards,
> > Tomasz
> >
next prev parent reply other threads:[~2019-05-16 8:48 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 10:04 [PATCH v3 0/2] Document memory-to-memory video codec interfaces Tomasz Figa
2019-01-24 10:04 ` [PATCH v3 1/2] media: docs-rst: Document memory-to-memory video decoder interface Tomasz Figa
2019-01-29 13:11 ` Hans Verkuil
2019-01-31 10:45 ` Hans Verkuil
2019-01-31 12:30 ` Hans Verkuil
2019-01-31 12:38 ` Hans Verkuil
2019-01-31 12:44 ` Philipp Zabel
2019-01-31 13:19 ` Hans Verkuil
2019-02-07 8:51 ` Tomasz Figa
2019-04-05 10:59 ` Philipp Zabel
2019-04-05 11:21 ` Hans Verkuil
2019-04-09 10:28 ` Tomasz Figa
2019-04-09 16:57 ` Philipp Zabel
2019-04-10 9:29 ` Hans Verkuil
2019-01-24 10:04 ` [PATCH v3 2/2] media: docs-rst: Document memory-to-memory video encoder interface Tomasz Figa
2019-01-29 13:52 ` Hans Verkuil
2019-03-14 13:57 ` Hans Verkuil
2019-04-05 8:12 ` Tomasz Figa
2019-04-05 10:03 ` Hans Verkuil
2019-04-08 9:23 ` Tomasz Figa
2019-04-08 11:11 ` Hans Verkuil
2019-04-09 9:35 ` Tomasz Figa
2019-04-10 8:50 ` Hans Verkuil
2019-04-10 16:05 ` Nicolas Dufresne
2019-04-15 8:56 ` Tomasz Figa
2019-04-15 12:30 ` Nicolas Dufresne
2019-04-05 5:53 ` Tomasz Figa
2019-04-05 7:09 ` Hans Verkuil
2019-03-21 10:10 ` Hans Verkuil
2019-04-08 6:59 ` Tomasz Figa
2019-04-08 7:43 ` Hans Verkuil
2019-04-08 9:35 ` Tomasz Figa
2019-03-25 13:12 ` Hans Verkuil
2019-03-25 16:33 ` Hans Verkuil
2019-04-08 8:40 ` Tomasz Figa
2019-04-08 8:36 ` Tomasz Figa
2019-04-08 8:43 ` Hans Verkuil
2019-04-09 7:11 ` Tomasz Figa
2019-04-09 9:37 ` Hans Verkuil
2019-04-09 9:43 ` Tomasz Figa
2019-05-22 8:43 ` Tomasz Figa
2019-05-22 8:51 ` Hans Verkuil
2019-05-22 14:16 ` Michael Tretter
2019-04-30 17:34 ` Michael Tretter
2019-05-14 8:12 ` Tomasz Figa
2019-05-16 8:37 ` Michael Tretter
2019-05-16 8:48 ` Tomasz Figa [this message]
2019-01-24 10:38 ` [PATCH v3 0/2] Document memory-to-memory video codec interfaces Hans Verkuil
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