From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ams-iport-2.cisco.com ([144.254.224.141]:38966 "EHLO ams-iport-2.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753055Ab3EVKhE (ORCPT ); Wed, 22 May 2013 06:37:04 -0400 From: Hans Verkuil To: Philipp Zabel Subject: Re: [RFC] [media] mem2mem: add support for hardware buffered queue Date: Wed, 22 May 2013 12:36:48 +0200 Cc: linux-media@vger.kernel.org, Mauro Carvalho Chehab , Pawel Osciak , John Sheu , Hans Verkuil References: <1369217856-10385-1-git-send-email-p.zabel@pengutronix.de> In-Reply-To: <1369217856-10385-1-git-send-email-p.zabel@pengutronix.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201305221236.48467.hverkuil@xs4all.nl> Sender: linux-media-owner@vger.kernel.org List-ID: On Wed 22 May 2013 12:17:36 Philipp Zabel wrote: > On mem2mem decoders with a hardware bitstream ringbuffer, to drain the > buffer at the end of the stream, remaining frames might need to be decoded > without additional input buffers being provided, and after calling streamoff > on the v4l2 output queue. This also allows a driver to copy input buffers > into their bitstream ringbuffer and immediately mark them as done to be > dequeued. > > The motivation for this patch is hardware assisted h.264 reordering support > in the coda driver. For high profile streams, the coda can hold back > out-of-order frames, causing a few mem2mem device runs in the beginning, that > don't produce any decompressed buffer at the v4l2 capture side. At the same > time, the last few frames can be decoded from the bitstream with mem2mem device > runs that don't need a new input buffer at the v4l2 output side. A streamoff > on the v4l2 output side can be used to put the decoder into the ringbuffer > draining end-of-stream mode. This is just a pointer to a related issue: how to signal to the application that the end-of-stream has been reached: http://www.mail-archive.com/linux-media@vger.kernel.org/msg60916.html How does the coda driver handle eos signalling? Regards, Hans