From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52DFCC433DF for ; Thu, 28 May 2020 10:48:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A8D2207D3 for ; Thu, 28 May 2020 10:48:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="MZO3K3g5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387925AbgE1Ksw (ORCPT ); Thu, 28 May 2020 06:48:52 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:12737 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387972AbgE1Ksw (ORCPT ); Thu, 28 May 2020 06:48:52 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1590662930; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=HNRdVG0VVJNpPaVdDgFiMrp7dCxngl8Gg955bDlBchY=; b=MZO3K3g5lkGp1WWCcVt7pJaPJII+zhLphiddCEZduYvSV7OkTesWn06siqhxOPevRevFQ7tk 0yZIIK+oTVEbaGH7FhVbWwOprvwnE594peQ+eelrss53EbgIHHKditk0jhJkiQPOPrMCJkDK HB6FHHvbgQrADwTwwAvP17ud5Go= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-east-1.postgun.com with SMTP id 5ecf96feea0dfa490e255e31 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 28 May 2020 10:48:30 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 52B74C433C6; Thu, 28 May 2020 10:48:29 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: dikshita) by smtp.codeaurora.org (Postfix) with ESMTPSA id B243DC433C9; Thu, 28 May 2020 10:48:27 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Thu, 28 May 2020 16:18:27 +0530 From: dikshita@codeaurora.org To: Hans Verkuil Cc: linux-media@vger.kernel.org, stanimir.varbanov@linaro.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, vgarodia@codeaurora.org, majja@codeaurora.org, jdas@codeaurora.org Subject: Re: [RFC] METADATA design using V4l2 Request API In-Reply-To: References: <1588918890-673-1-git-send-email-dikshita@codeaurora.org> Message-ID: X-Sender: dikshita@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Hans, Thanks for the review. On 2020-05-26 16:27, Hans Verkuil wrote: > Hi Dikshita, > > My apologies for the delay, this was (mostly) due to various vacation > days. > > On 08/05/2020 08:21, Dikshita Agarwal wrote: >> There are many commercialized video use cases which needs metadata >> info >> to be circulated between v4l2 client and v4l2 driver. >> >> METADATA has following requirements associated: >> •Metadata is an optional info available for a buffer. It is not >> mandatorily for every buffer. >> For ex. consider metadata ROI (Region Of Interest). ROI is specified >> by clients to indicate >> the region where enhanced quality is desired. This metadata is given >> as an input information >> to encoder output plane. Client may or may not specify the ROI for a >> frame during encode as >> an input metadata. Also if the client has not provided ROI metadata >> for a given frame, >> it would be incorrect to take the metadata from previous frame. If >> the data and >> metadata is asynchronous, it would be difficult for hardware to >> decide if it >> needs to wait for metadata buffer or not before processing the input >> frame for encoding. >> •Synchronize the buffer requirement across both the video node/session >> (incase metadata is being processed as a separate v4l2 video >> node/session). >> This is to avoid buffer starvation. >> •Associate the metadata buffer with the data buffer without adding any >> pipeline delay >> in waiting for each other. This is applicable both at the hardware >> side (the processing end) >> and client side (the receiving end). >> •Low latency usecases like WFD/split rendering/game streaming/IMS have >> sub-50ms e2e latency >> requirements, and it is not practical to stall the pipeline due to >> inherent framework latencies. >> High performance usecase like high-frame rate playback/record can >> lead to frame loss during any pipeline latency. >> >> To address all above requirements, we used v4l2 Request API as >> interlace. >> >> As an experiment, We have introduced new control >> V4L2_CID_MPEG_VIDEO_VENUS_METADATA >> to contain the METADATA info. Exact controls can be finalized once the >> interface is discussed. >> >> For setting metadata from userspace to kernel, let say on encode >> output plane, >> following code sequence was followed >> 1. Video driver is registering for media device and creating a media >> node in /dev >> 2. Request fd is allocated by calling MEDIA_IOC_REQUEST_ALLOC IOCTL on >> media fd. >> 3. METADATA configuration is being applied on request fd using >> VIDIOC_S_EXT_CTRLS IOCTL >> and the same request fd is added to buf structure structure before >> calling VIDIOC_QBUF on video fd. >> 4. The same request is queued through MEDIA_REQUEST_IOC_QUEUE IOCTL to >> driver then, as a result >> to which METADATA control will be applied to buffer through S_CTRL. >> 5. Once control is applied and request is completed, >> MEDIA_REQUEST_IOC_REINIT IOCTL is called >> to re-initialize the request. > > This is fine and should work well. It's what the Request API is for, > so no problems here. > >> >> We could achieve the same on capture plane as well by removing few >> checks present currently >> in v4l2 core which restrict the implementation to only output plane. > > Why do you need the Request API for the capture side in a > memory-to-memory driver? It is not > clear from this patch series what the use-case is. There are reasons > why this is currently > not allowed. So I need to know more about this. > > Regards, > > Hans > we need this for use cases like HDR10+ where metadata info is part of the bitstream. To handle such frame specific data, support for request api on capture plane would be needed. Thanks, Dikshita >> >> We profiled below data with this implementation : >> 1. Total time taken ( round trip ) for setting up control data on >> video driver >> with VIDIOC_S_EXT_CTRLS, QBUF and Queue Request: 737us >> 2. Time taken for first QBUF on Output plane to reach driver with >> REQUEST API enabled (One way): 723us >> 3. Time taken for first QBUF on Output plane to reach driver without >> REQUEST API (One way) : 250us >> 4. Time taken by each IOCTL to complete ( round trip ) with REQUEST >> API enabled : >> a. VIDIOC_S_EXT_CTRLS : 201us >> b. VIDIOC_QBUF : 92us >> c. MEDIA_REQUEST_IOC_QUEUE: 386us >> >> Kindly share your feedback/comments on the design/call sequence. >> Also as we experimented and enabled the metadata on capture plane as >> well, please comment if any issue in >> allowing the metadata exchange on capture plane as well. >> >> Reference for client side implementation can be found at [1]. >> >> Thanks, >> Dikshita >> >> [1] >> https://git.linaro.org/people/stanimir.varbanov/v4l2-encode.git/log/?h=dikshita/request-api >> >> Dikshita Agarwal (3): >> Register for media device >> - Initialize and register for media device >> - define venus_m2m_media_ops >> - Implement APIs to register/unregister media controller. >> Enable Request API for output buffers >> - Add dependency on MEDIA_CONTROLLER_REQUEST_API in Kconfig. >> - Initialize vb2 ops buf_out_validate and buf_request_complete. >> - Add support for custom Metadata control >> V4L2_CID_MPEG_VIDEO_VENUS_METADATA >> - Implemeted/Integrated APIs for Request setup/complete. >> Enable Request API for Capture Buffers >> >> drivers/media/common/videobuf2/videobuf2-v4l2.c | 4 +- >> drivers/media/platform/Kconfig | 2 +- >> drivers/media/platform/qcom/venus/core.h | 36 ++++ >> drivers/media/platform/qcom/venus/helpers.c | 247 >> +++++++++++++++++++++++- >> drivers/media/platform/qcom/venus/helpers.h | 15 ++ >> drivers/media/platform/qcom/venus/venc.c | 63 +++++- >> drivers/media/platform/qcom/venus/venc_ctrls.c | 61 +++++- >> drivers/media/v4l2-core/v4l2-ctrls.c | 10 + >> drivers/media/v4l2-core/v4l2-mem2mem.c | 17 +- >> include/media/v4l2-ctrls.h | 1 + >> include/media/venus-ctrls.h | 22 +++ >> 11 files changed, 465 insertions(+), 13 deletions(-) >> create mode 100644 include/media/venus-ctrls.h >>