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 24BB445EFA for ; Mon, 17 Apr 2023 17:25:25 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7BFDC68BE67; Mon, 17 Apr 2023 20:25:23 +0300 (EEST) Received: from w4.tutanota.de (w4.tutanota.de [81.3.6.165]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 2E5EA6802C4 for ; Mon, 17 Apr 2023 20:25:17 +0300 (EEST) Received: from tutadb.w10.tutanota.de (unknown [192.168.1.10]) by w4.tutanota.de (Postfix) with ESMTP id DCC07106015C for ; Mon, 17 Apr 2023 17:25:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1681752316; s=s1; d=lynne.ee; h=From:From:To:To:Subject:Subject:Content-Description:Content-ID:Content-Type:Content-Type:Content-Transfer-Encoding:Content-Transfer-Encoding:Cc:Date:Date:In-Reply-To:In-Reply-To:MIME-Version:MIME-Version:Message-ID:Message-ID:Reply-To:References:References:Sender; bh=3hty5aM5kO6zAkdIytk6lFY/5pzRydH/sz6m49Yb69E=; b=zRbiIwBv3KY7P7udmg1b/DUd+14yYrJm26qAvwz651HDVX9hdBn3wxAEyEtAexrD V0Zs6f2fiLp44PAFolyXewwW+qHhEW0wZJ4EvmzCSZ6pmVTlvWOHEzArGWdWrwmzdPD MCyIH/iM6SP6iw/W+DItXPw2BziAwjnEtueLX4BVefKJO0rUN9uODEGSkYEsRX8DoeP r1gZQz8ZWSZliUEAgrFuoF1VRnoEqS+Td3ngrvLILRnuBAhJjekWeqJT2dbiXBrG1M1 mrXDg1GhFkejViO0euhUrqcoUvtQpAejjA2nK1ElTEQaMODr7h+JD4QUo1ejrNetABM zM8DMP6xog== Date: Mon, 17 Apr 2023 19:25:16 +0200 (CEST) From: Lynne To: FFmpeg development discussions and patches Message-ID: In-Reply-To: References: <20230417143930.1186-1-jamrial@gmail.com> MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH] avutil/frame: use bitfields for some boolean and enum fields 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Apr 17, 2023, 17:15 by jamrial@gmail.com: > On 4/17/2023 12:00 PM, Lynne wrote: > >> Apr 17, 2023, 16:40 by jamrial@gmail.com: >> >>> Should reduce the size of AVFrame in the next major bump without changing the API. >>> >>> Suggested-by: Anton Khirnov >>> Signed-off-by: James Almer >>> --- >>> This supersedes "avutil/frame: add new interlaced and top_field_first flags" >>> and "avutil/frame: add a keyframe flag to AVFrame". >>> >>> libavutil/frame.h | 56 +++++++++++++++++++++++++++++++++++++++++++++ >>> libavutil/version.h | 1 + >>> 2 files changed, 57 insertions(+) >>> >>> diff --git a/libavutil/frame.h b/libavutil/frame.h >>> index f85d630c5c..c26067f383 100644 >>> --- a/libavutil/frame.h >>> +++ b/libavutil/frame.h >>> @@ -416,6 +416,7 @@ typedef struct AVFrame { >>> */ >>> int format; >>> +#if FF_API_BITFIELDS >>> /** >>> * 1 -> keyframe, 0-> not >>> */ >>> @@ -425,6 +426,57 @@ typedef struct AVFrame { >>> * Picture type of the frame. >>> */ >>> enum AVPictureType pict_type; >>> +#else >>> + /** >>> + * 1 -> keyframe, 0-> not >>> + */ >>> + unsigned int key_frame: 1; >>> + >>> + /** >>> + * The content of the picture is interlaced. >>> + */ >>> + unsigned int interlaced_frame: 1; >>> + >>> + /** >>> + * If the content is interlaced, is top field displayed first. >>> + */ >>> + unsigned int top_field_first: 1; >>> + >>> + /** >>> + * Tell user application that palette has changed from previous frame. >>> + */ >>> + unsigned int palette_has_changed: 1; >>> + >>> + /** >>> + * Reserved. Must not be touched. >>> + */ >>> + unsigned int reserved_bitfield: (sizeof(unsigned int) * 8) - 9; >>> + >>> + /** >>> + * MPEG vs JPEG YUV range. >>> + * - encoding: Set by user >>> + * - decoding: Set by libavcodec >>> + */ >>> + enum AVColorRange color_range: 2; >>> + >>> + enum AVChromaLocation chroma_location: 3; >>> >> >> Definitely disagree on all non-8bit field limits. >> The reserved_bitfield is especially ugly. >> A few wasted bits wouldn't affect much, we don't even support building on 6502s. >> Use bools, or limit them to 8bits so we can use bools when we bump? >> The rest can be limited to 8bits. >> > > I added reserved_bitfield to turn what otherwise will be compiler-injected padding into something that can be reused if we were to add new fields here instead of at the end of the struct. I can remove it if you prefer, and make color_range and chroma_location into :8. > Like i told you on IRC, i want to keep these as enum and not change their type to uint8_t, _Bool, or anything like that. Also, i wouldn't be surprised if using _Bool breaks some old weird compilers. > > With this change, I'm replacing 40 bytes worth of fields with 8 bytes worth of fields with no API break. > I'm fine with enums staying as enums, and limiting them to 8 bits. I'm not fine with limiting flags to 1 bit or 2/3 bits. I'd like for them to be limited to 8 bits, and changing their type to bool or uint8_t at the bump. You're still saving at least 21 bytes. _______________________________________________ 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".