From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:44276 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753800AbaDJWgF (ORCPT ); Thu, 10 Apr 2014 18:36:05 -0400 Message-ID: <53471CD3.3060306@iki.fi> Date: Fri, 11 Apr 2014 01:36:03 +0300 From: Sakari Ailus MIME-Version: 1.0 To: Laurent Pinchart CC: linux-media@vger.kernel.org Subject: Re: [yavta PATCH 7/9] Print timestamp type and source for dequeued buffers References: <1393690690-5004-1-git-send-email-sakari.ailus@iki.fi> <5116965.JxiWPkm0Gp@avalon> <5346E9E1.2080702@iki.fi> <1981061.t1Onuu4osC@avalon> In-Reply-To: <1981061.t1Onuu4osC@avalon> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Laurent Pinchart wrote: > On Thursday 10 April 2014 21:58:41 Sakari Ailus wrote: >> Laurent Pinchart wrote: >>> Hi Sakari, >>> >>> Thank you for the patch. >>> >>> Given that the timestamp type and source are not supposed to change during >>> streaming, do we really need to print them for every frame ? >> >> When processing frames from memory to memory (COPY timestamp type), the >> it is entirely possible that the timestamp source changes as the flags >> are copied from the OUTPUT buffer to the CAPTURE buffer. > > It's possible, but is it allowed by the V4L2 API ? The spec states that: "The V4L2_BUF_FLAG_TIMESTAMP_COPY timestamp type which is used by e.g. on mem-to-mem devices is an exception to the rule: the timestamp source flags are copied from the OUTPUT video buffer to the CAPTURE video buffer." >> These patches do not support it but it is allowed. >> >> One option would be to print the source on every frame only when the >> type is COPY. For a program like yavta this might be overly >> sophisticated IMO. :-) > > My concern is that this makes the lines output by yavta pretty long. True as well. I could remove "type/src " from the timestamp source information. That's mostly redundant anyway. Then we shouldn't exceed 80 characters per line that easily anymore. Could this be the time to add a "verbose" option? :-) -- Regards, Sakari Ailus sakari.ailus@iki.fi