Re: [PATCH v5 1/5] [media] DocBook media: document mem2mem draining flow
On 05/04/2015 12:21 PM, Philipp Zabel wrote: > Hi Hans, Kamil, > > thank you for your comments. > > Am Montag, den 27.04.2015, 15:23 +0200 schrieb Hans Verkuil: >> Hi Philipp, >> >> I finally got around to reviewing this patch series. Sorry for the delay, but >> here are my comments: >> >> On 04/20/2015 10:28 AM, Philipp Zabel wrote: >>> Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and >>> VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the >>> V4L2_EVENT_EOS >>> event signalling all capture buffers are finished and ready to be dequeud, >>> the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being >>> dequeued >>> from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values >>> once >>> the queue is drained. >>> >>> Signed-off-by: Philipp Zabel >>> --- >>> Changes since v4: >>> - Split out documentation changes into a separate patch >>> - Changed wording following Pawel's suggestions. >>> --- >>> Documentation/DocBook/media/v4l/io.xml | 10 ++ >>> Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 9 - >>> Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 8 +++- >>> Documentation/DocBook/media/v4l/vidioc-qbuf.xml| 8 >>> 4 files changed, 33 insertions(+), 2 deletions(-) >>> >>> diff --git a/Documentation/DocBook/media/v4l/io.xml >>> b/Documentation/DocBook/media/v4l/io.xml >>> index 1c17f80..f561037 100644 >>> --- a/Documentation/DocBook/media/v4l/io.xml >>> +++ b/Documentation/DocBook/media/v4l/io.xml >>> @@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but >>> by some DMA-capable unit, >>> in which case caches have not been used. >>> >>> >>> + V4L2_BUF_FLAG_LAST >>> + 0x0010 >>> + Last buffer produced by the hardware. mem2mem codec drivers >>> +set this flag on the capture queue for the last buffer when the >>> +VIDIOC_QUERYBUF or >>> +VIDIOC_DQBUF ioctl is called. Any >>> subsequent >>> +call to the VIDIOC_DQBUF ioctl will not >>> block >>> +anymore, but return an &EPIPE;. >> >> As Kamil mentioned in his review, we should allow for bytesused == 0 here. > > How about: > > @@ -1134,9 +1134,11 @@ in which case caches have not been used. > Last buffer produced by the hardware. mem2mem codec drivers > set this flag on the capture queue for the last buffer when the > VIDIOC_QUERYBUF or > -VIDIOC_DQBUF ioctl is called. Any > subsequent > -call to the VIDIOC_DQBUF ioctl will not > block > -anymore, but return an &EPIPE;. > +VIDIOC_DQBUF ioctl is called. Due to > hardware > +limitations, the last buffer may be empty. In this case the driver will set > the > +bytesused field to 0, regardless of the format. > Any > +Any subsequent call to the VIDIOC_DQBUF > ioctl > +will not block anymore, but return an &EPIPE;. > > > V4L2_BUF_FLAG_TIMESTAMP_MASK > >>> + >>> + >>> V4L2_BUF_FLAG_TIMESTAMP_MASK >>> 0xe000 >>> Mask for timestamp types below. To test the >>> diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml >>> b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml >>> index 9215627..6502d82 100644 >>> --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml >>> +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml >>> @@ -197,7 +197,14 @@ be muted when playing back at a non-standard speed. >>> this command does nothing. This command has two flags: >>> if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the >>> decoder will >>> set the picture to black after it stopped decoding. Otherwise the last >>> image will >>> -repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then >>> the decoder >>> +repeat. mem2mem decoders will stop producing new frames altogether. They >>> will send >>> +a V4L2_EVENT_EOS event when the last frame has been >>> decoded >>> +and all frames are ready to be dequeued and will set the >>> +V4L2_BUF_FLAG_LAST buffer flag on the last buffer of >>> the >> >> Make a note here as well that the last buffer might be an empty buffer. > > @@ -201,9 +201,12 @@ repeat. mem2mem decoders will stop producing new frames > altogether. They will se > a V4L2_EVENT_EOS event when the last frame has been > decoded > and all frames are ready to be dequeued and will set the > V4L2_BUF_FLAG_LAST buffer flag on the last buffer of the > -capture queue to indicate there will be no new buffers produced to dequeue. > Once > -this flag was set, the VIDIOC_DQBUF ioctl > -will not block anymore, but return an &EPIPE;. > +capture queue to indicate there will be no new buffers produced to dequeue. > This > +buffer may be empty, indicated by the driver setting the > +bytesused field to 0. Once the > +V4L2_BUF_FLAG_LAST flag was set, the > +VIDIOC_DQBUF ioctl will not block anymore, > +but return an &EPIPE;. > If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the > decoder > stops immediately (ignori
Re: [PATCH v5 1/5] [media] DocBook media: document mem2mem draining flow
Hi Hans, Kamil, thank you for your comments. Am Montag, den 27.04.2015, 15:23 +0200 schrieb Hans Verkuil: > Hi Philipp, > > I finally got around to reviewing this patch series. Sorry for the delay, but > here are my comments: > > On 04/20/2015 10:28 AM, Philipp Zabel wrote: > > Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and > > VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the > > V4L2_EVENT_EOS > > event signalling all capture buffers are finished and ready to be dequeud, > > the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being > > dequeued > > from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values > > once > > the queue is drained. > > > > Signed-off-by: Philipp Zabel > > --- > > Changes since v4: > > - Split out documentation changes into a separate patch > > - Changed wording following Pawel's suggestions. > > --- > > Documentation/DocBook/media/v4l/io.xml | 10 ++ > > Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 9 - > > Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 8 +++- > > Documentation/DocBook/media/v4l/vidioc-qbuf.xml| 8 > > 4 files changed, 33 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/DocBook/media/v4l/io.xml > > b/Documentation/DocBook/media/v4l/io.xml > > index 1c17f80..f561037 100644 > > --- a/Documentation/DocBook/media/v4l/io.xml > > +++ b/Documentation/DocBook/media/v4l/io.xml > > @@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but > > by some DMA-capable unit, > > in which case caches have not been used. > > > > > > + V4L2_BUF_FLAG_LAST > > + 0x0010 > > + Last buffer produced by the hardware. mem2mem codec drivers > > +set this flag on the capture queue for the last buffer when the > > +VIDIOC_QUERYBUF or > > +VIDIOC_DQBUF ioctl is called. Any > > subsequent > > +call to the VIDIOC_DQBUF ioctl will not > > block > > +anymore, but return an &EPIPE;. > > As Kamil mentioned in his review, we should allow for bytesused == 0 here. How about: @@ -1134,9 +1134,11 @@ in which case caches have not been used. Last buffer produced by the hardware. mem2mem codec drivers set this flag on the capture queue for the last buffer when the VIDIOC_QUERYBUF or -VIDIOC_DQBUF ioctl is called. Any subsequent -call to the VIDIOC_DQBUF ioctl will not block -anymore, but return an &EPIPE;. +VIDIOC_DQBUF ioctl is called. Due to hardware +limitations, the last buffer may be empty. In this case the driver will set the +bytesused field to 0, regardless of the format. Any +Any subsequent call to the VIDIOC_DQBUF ioctl +will not block anymore, but return an &EPIPE;. V4L2_BUF_FLAG_TIMESTAMP_MASK > > + > > + > > V4L2_BUF_FLAG_TIMESTAMP_MASK > > 0xe000 > > Mask for timestamp types below. To test the > > diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > > b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > > index 9215627..6502d82 100644 > > --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > > +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > > @@ -197,7 +197,14 @@ be muted when playing back at a non-standard speed. > > this command does nothing. This command has two flags: > > if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the > > decoder will > > set the picture to black after it stopped decoding. Otherwise the last > > image will > > -repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then > > the decoder > > +repeat. mem2mem decoders will stop producing new frames altogether. They > > will send > > +a V4L2_EVENT_EOS event when the last frame has been > > decoded > > +and all frames are ready to be dequeued and will set the > > +V4L2_BUF_FLAG_LAST buffer flag on the last buffer of > > the > > Make a note here as well that the last buffer might be an empty buffer. @@ -201,9 +201,12 @@ repeat. mem2mem decoders will stop producing new frames altogether. They will se a V4L2_EVENT_EOS event when the last frame has been decoded and all frames are ready to be dequeued and will set the V4L2_BUF_FLAG_LAST buffer flag on the last buffer of the -capture queue to indicate there will be no new buffers produced to dequeue. Once -this flag was set, the VIDIOC_DQBUF ioctl -will not block anymore, but return an &EPIPE;. +capture queue to indicate there will be no new buffers produced to dequeue. This +buffer may be empty, indicated by the driver setting the +bytesused field to 0. Once the +V4L2_BUF_FLAG_LAST flag was set, the +VIDIOC_DQBUF ioctl will not block anymore, +but return an &EPIPE;. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the decoder stops immediately (ignoring the pts value), otherwise it will keep decoding until timestamp >= pts or until the last of the pending data from > > +capture queue to indicate ther
Re: [PATCH v5 1/5] [media] DocBook media: document mem2mem draining flow
On 04/20/2015 10:28 AM, Philipp Zabel wrote: > Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and > VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the V4L2_EVENT_EOS > event signalling all capture buffers are finished and ready to be dequeud, > the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being > dequeued > from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values once > the queue is drained. Actually, we document the m2m draining flow, but the same thing is true for MPEG capture devices like hdpvr that support ENCODER_CMD. So I don't think this is specific to m2m devices. Regards, Hans > > Signed-off-by: Philipp Zabel > --- > Changes since v4: > - Split out documentation changes into a separate patch > - Changed wording following Pawel's suggestions. > --- > Documentation/DocBook/media/v4l/io.xml | 10 ++ > Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 9 - > Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 8 +++- > Documentation/DocBook/media/v4l/vidioc-qbuf.xml| 8 > 4 files changed, 33 insertions(+), 2 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/io.xml > b/Documentation/DocBook/media/v4l/io.xml > index 1c17f80..f561037 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but by > some DMA-capable unit, > in which case caches have not been used. > > > + V4L2_BUF_FLAG_LAST > + 0x0010 > + Last buffer produced by the hardware. mem2mem codec drivers > +set this flag on the capture queue for the last buffer when the > +VIDIOC_QUERYBUF or > +VIDIOC_DQBUF ioctl is called. Any > subsequent > +call to the VIDIOC_DQBUF ioctl will not > block > +anymore, but return an &EPIPE;. > + > + > V4L2_BUF_FLAG_TIMESTAMP_MASK > 0xe000 > Mask for timestamp types below. To test the > diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > index 9215627..6502d82 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > @@ -197,7 +197,14 @@ be muted when playing back at a non-standard speed. > this command does nothing. This command has two flags: > if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the decoder > will > set the picture to black after it stopped decoding. Otherwise the last image > will > -repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then > the decoder > +repeat. mem2mem decoders will stop producing new frames altogether. They > will send > +a V4L2_EVENT_EOS event when the last frame has been > decoded > +and all frames are ready to be dequeued and will set the > +V4L2_BUF_FLAG_LAST buffer flag on the last buffer of the > +capture queue to indicate there will be no new buffers produced to dequeue. > Once > +this flag was set, the VIDIOC_DQBUF ioctl > +will not block anymore, but return an &EPIPE;. > +If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the > decoder > stops immediately (ignoring the pts value), > otherwise it > will keep decoding until timestamp >= pts or until the last of the pending > data from > its internal buffers was decoded. > diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > index 0619ca5..3cdb841 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > @@ -129,7 +129,13 @@ this command. > encoding will continue until the end of the current Group > Of Pictures, otherwise encoding will stop immediately. > When the encoder is already stopped, this command does > -nothing. > +nothing. mem2mem encoders will send a V4L2_EVENT_EOS > event > +when the last frame has been decoded and all frames are ready to be dequeued > and > +will set the V4L2_BUF_FLAG_LAST buffer flag on the last > +buffer of the capture queue to indicate there will be no new buffers > produced to > +dequeue. Once this flag was set, the > +VIDIOC_DQBUF ioctl will not block anymore, > +but return an &EPIPE;. > > > V4L2_ENC_CMD_PAUSE > diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > index 3504a7f..6cfc53b 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > @@ -186,6 +186,14 @@ In that case the application should be able to safely > reuse the buffer and > continue streaming. > > > + EPIPE > + > + VIDIOC_DQBUF returns this on an empty > +capture queue for mem2mem codecs if a buffer with the > +V4L2_BUF_FLAG_LAST was already dequ
Re: [PATCH v5 1/5] [media] DocBook media: document mem2mem draining flow
Hi Philipp, I finally got around to reviewing this patch series. Sorry for the delay, but here are my comments: On 04/20/2015 10:28 AM, Philipp Zabel wrote: > Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and > VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the V4L2_EVENT_EOS > event signalling all capture buffers are finished and ready to be dequeud, > the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being > dequeued > from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values once > the queue is drained. > > Signed-off-by: Philipp Zabel > --- > Changes since v4: > - Split out documentation changes into a separate patch > - Changed wording following Pawel's suggestions. > --- > Documentation/DocBook/media/v4l/io.xml | 10 ++ > Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 9 - > Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 8 +++- > Documentation/DocBook/media/v4l/vidioc-qbuf.xml| 8 > 4 files changed, 33 insertions(+), 2 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/io.xml > b/Documentation/DocBook/media/v4l/io.xml > index 1c17f80..f561037 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but by > some DMA-capable unit, > in which case caches have not been used. > > > + V4L2_BUF_FLAG_LAST > + 0x0010 > + Last buffer produced by the hardware. mem2mem codec drivers > +set this flag on the capture queue for the last buffer when the > +VIDIOC_QUERYBUF or > +VIDIOC_DQBUF ioctl is called. Any > subsequent > +call to the VIDIOC_DQBUF ioctl will not > block > +anymore, but return an &EPIPE;. As Kamil mentioned in his review, we should allow for bytesused == 0 here. > + > + > V4L2_BUF_FLAG_TIMESTAMP_MASK > 0xe000 > Mask for timestamp types below. To test the > diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > index 9215627..6502d82 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml > @@ -197,7 +197,14 @@ be muted when playing back at a non-standard speed. > this command does nothing. This command has two flags: > if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the decoder > will > set the picture to black after it stopped decoding. Otherwise the last image > will > -repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then > the decoder > +repeat. mem2mem decoders will stop producing new frames altogether. They > will send > +a V4L2_EVENT_EOS event when the last frame has been > decoded > +and all frames are ready to be dequeued and will set the > +V4L2_BUF_FLAG_LAST buffer flag on the last buffer of the Make a note here as well that the last buffer might be an empty buffer. > +capture queue to indicate there will be no new buffers produced to dequeue. > Once > +this flag was set, the VIDIOC_DQBUF ioctl > +will not block anymore, but return an &EPIPE;. > +If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the > decoder > stops immediately (ignoring the pts value), > otherwise it > will keep decoding until timestamp >= pts or until the last of the pending > data from > its internal buffers was decoded. > diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > index 0619ca5..3cdb841 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml > @@ -129,7 +129,13 @@ this command. > encoding will continue until the end of the current Group > Of Pictures, otherwise encoding will stop immediately. > When the encoder is already stopped, this command does > -nothing. > +nothing. mem2mem encoders will send a V4L2_EVENT_EOS > event > +when the last frame has been decoded and all frames are ready to be dequeued > and > +will set the V4L2_BUF_FLAG_LAST buffer flag on the last > +buffer of the capture queue to indicate there will be no new buffers > produced to Ditto. > +dequeue. Once this flag was set, the > +VIDIOC_DQBUF ioctl will not block anymore, > +but return an &EPIPE;. > > > V4L2_ENC_CMD_PAUSE > diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > index 3504a7f..6cfc53b 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml > @@ -186,6 +186,14 @@ In that case the application should be able to safely > reuse the buffer and > continue streaming. > > > + EPIPE > + > + VIDIOC_DQBUF returns this on an empty > +capture queue for mem2mem co
[PATCH v5 1/5] [media] DocBook media: document mem2mem draining flow
Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the V4L2_EVENT_EOS event signalling all capture buffers are finished and ready to be dequeud, the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being dequeued from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values once the queue is drained. Signed-off-by: Philipp Zabel --- Changes since v4: - Split out documentation changes into a separate patch - Changed wording following Pawel's suggestions. --- Documentation/DocBook/media/v4l/io.xml | 10 ++ Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 9 - Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml | 8 +++- Documentation/DocBook/media/v4l/vidioc-qbuf.xml| 8 4 files changed, 33 insertions(+), 2 deletions(-) diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 1c17f80..f561037 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -1129,6 +1129,16 @@ in this buffer has not been created by the CPU but by some DMA-capable unit, in which case caches have not been used. + V4L2_BUF_FLAG_LAST + 0x0010 + Last buffer produced by the hardware. mem2mem codec drivers +set this flag on the capture queue for the last buffer when the +VIDIOC_QUERYBUF or +VIDIOC_DQBUF ioctl is called. Any subsequent +call to the VIDIOC_DQBUF ioctl will not block +anymore, but return an &EPIPE;. + + V4L2_BUF_FLAG_TIMESTAMP_MASK 0xe000 Mask for timestamp types below. To test the diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml index 9215627..6502d82 100644 --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml @@ -197,7 +197,14 @@ be muted when playing back at a non-standard speed. this command does nothing. This command has two flags: if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the decoder will set the picture to black after it stopped decoding. Otherwise the last image will -repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the decoder +repeat. mem2mem decoders will stop producing new frames altogether. They will send +a V4L2_EVENT_EOS event when the last frame has been decoded +and all frames are ready to be dequeued and will set the +V4L2_BUF_FLAG_LAST buffer flag on the last buffer of the +capture queue to indicate there will be no new buffers produced to dequeue. Once +this flag was set, the VIDIOC_DQBUF ioctl +will not block anymore, but return an &EPIPE;. +If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the decoder stops immediately (ignoring the pts value), otherwise it will keep decoding until timestamp >= pts or until the last of the pending data from its internal buffers was decoded. diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml index 0619ca5..3cdb841 100644 --- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml @@ -129,7 +129,13 @@ this command. encoding will continue until the end of the current Group Of Pictures, otherwise encoding will stop immediately. When the encoder is already stopped, this command does -nothing. +nothing. mem2mem encoders will send a V4L2_EVENT_EOS event +when the last frame has been decoded and all frames are ready to be dequeued and +will set the V4L2_BUF_FLAG_LAST buffer flag on the last +buffer of the capture queue to indicate there will be no new buffers produced to +dequeue. Once this flag was set, the +VIDIOC_DQBUF ioctl will not block anymore, +but return an &EPIPE;. V4L2_ENC_CMD_PAUSE diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml index 3504a7f..6cfc53b 100644 --- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml @@ -186,6 +186,14 @@ In that case the application should be able to safely reuse the buffer and continue streaming. + EPIPE + + VIDIOC_DQBUF returns this on an empty +capture queue for mem2mem codecs if a buffer with the +V4L2_BUF_FLAG_LAST was already dequeued and no new buffers +are expected to become available. + + -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
