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 ACD9640AE1 for ; Tue, 5 Jul 2022 11:30:19 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 9AB3168B9CA; Tue, 5 Jul 2022 14:30:17 +0300 (EEST) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 396AC68B8F2 for ; Tue, 5 Jul 2022 14:30:11 +0300 (EEST) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id 6D299240179 for ; Tue, 5 Jul 2022 13:30:10 +0200 (CEST) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id s4Rl0BvgnTDX for ; Tue, 5 Jul 2022 13:30:09 +0200 (CEST) Received: from lain.khirnov.net (lain.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 566FA2400F5 for ; Tue, 5 Jul 2022 13:30:09 +0200 (CEST) Received: by lain.khirnov.net (Postfix, from userid 1000) id 97BDE1601B2; Tue, 5 Jul 2022 13:30:09 +0200 (CEST) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: =?utf-8?q?=3CDB6PR0101MB22149D72563A594BAD63E8BF8FBF9=40DB6PR01?= =?utf-8?q?01MB2214=2Eeurprd01=2Eprod=2Eexchangelabs=2Ecom=3E?= References: <20220703102636.32523-1-anton@khirnov.net> <20220703102636.32523-2-anton@khirnov.net> =?utf-8?q?=3CDB6PR0101MB22149D72?= =?utf-8?q?563A594BAD63E8BF8FBF9=40DB6PR0101MB2214=2Eeurprd01=2Eprod=2Eexcha?= =?utf-8?q?ngelabs=2Ecom=3E?= Mail-Followup-To: FFmpeg development discussions and patches Date: Tue, 05 Jul 2022 13:30:09 +0200 Message-ID: <165702060959.31466.15042894037922690444@lain.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH 2/3] lavc: add standalone cached bitstream reader 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: Quoting Andreas Rheinhardt (2022-07-03 15:16:39) > Anton Khirnov: > > + > > +#include "mathops.h" > > What exactly is mathops.h for? get_bits.h uses it for NEG_USR32 and > NEG_SSR32, but you are not using it here. sign_extend()? > > +/** > > + * Skip bits to a byte boundary. > > + */ > > +static inline const uint8_t *bits_align(BitstreamContext *bc) > > +{ > > + unsigned int n = -bits_tell(bc) & 7; > > + if (n) > > + bits_skip(bc, n); > > Is there a reason that I don't see that makes you not simply use > bc->bits_left &= ~0xff? I don't see how that is supposed to work. > > > + return bc->buffer + (bits_tell(bc) >> 3); > > +} > > + > > +/** > > + * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). > > + * If MSB not set it is negative. > > + * @param n length in bits > > + */ > > +static inline int bits_read_xbits(BitstreamContext *bc, unsigned int n) > > +{ > > + int32_t cache = bits_peek(bc, 32); > > + int sign = ~cache >> 31; > > + bits_priv_skip_remaining(bc, n); > > FYI: You are potentially skipping more bits here than you have. Yes, you made that clear in your fake-caching patch. Do you require that be fixed now? Or can this go in, then we apply some form of your patch? > > +/* Read sign bit and flip the sign of the provided value accordingly. */ > > +static inline int bits_apply_sign(BitstreamContext *bc, int val) > > +{ > > + int sign = bits_read_signed(bc, 1); > > Is there a reason you are not using bits_read_bit here? I want a signed result. -- Anton Khirnov _______________________________________________ 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".