From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 96CCC42B81 for ; Wed, 27 Apr 2022 13:32:05 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 6C87B68B413; Wed, 27 Apr 2022 16:32:02 +0300 (EEST) Received: from mout-p-202.mailbox.org (mout-p-202.mailbox.org [80.241.56.172]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 919BD68B3F7 for ; Wed, 27 Apr 2022 16:31:53 +0300 (EEST) Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 4KpKRF3fyxz9sX7 for ; Wed, 27 Apr 2022 15:31:53 +0200 (CEST) Message-ID: <4a58f1a8-5e55-7e90-1716-f53cf712f6a1@gyani.pro> Date: Wed, 27 Apr 2022 19:01:37 +0530 MIME-Version: 1.0 Content-Language: en-US To: ffmpeg-devel@ffmpeg.org References: <20220426210834.314078-1-leo.izen@gmail.com> <52349af0-efb6-e5ed-9e20-ad4c03faa2f0@gmail.com> From: Gyan Doshi In-Reply-To: <52349af0-efb6-e5ed-9e20-ad4c03faa2f0@gmail.com> Subject: Re: [FFmpeg-devel] [PATCH] doc/encoders: document libjxl encoder options X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 2022-04-27 05:58 pm, Leo Izen wrote: > On 4/27/22 04:39, Gyan Doshi wrote: >> >> >> On 2022-04-27 02:38 am, Leo Izen wrote: >>> >>> + >>> +@item modular >>> +Force the encoder to use Modular mode. The default is to let the >>> encoder pick >>> +between VarDCT and Modular encoding modes based on encoding >>> settings and the >>> +type of input content. >> >> What happens in these two modes? Why would the user want to force >> modular? Is there a way and reason to force VarDCT? >> >> > VarDCT uses a fourier-DCT-based transform in essence. Modular uses a > variety of transforms that can be combined like Lego bricks into > patches, including a modified Haar transform. > > In general, VarDCT will be superior to Modular for lossy encoding, but > VarDCT doesn't support lossless, so Modular is required for lossless > encoding. Currently, the library always chooses VarDCT for lossy and > Modular for lossless, although this could potentially be subject to > change. > > A user will have very little reason to force modular unless they're > testing the two modes against each other. The library API does not > provide a way to force VarDCT. Or rather, it does, but if you force > VarDCT and tell it to encode losslessly it will silently use modular > rather than fail. > > You generally won't have a reason to force VarDCT anyway, since it's > chosen by default if you pick lossy, so this isn't an issue. Ok, maybe qualify the option description to state lossless is always modular and lossy is VarDCT unless forced otherwise. LGTM with those changes. Regards, Gyan _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".