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 ESMTPS id 6F8A44E2D8 for ; Wed, 30 Apr 2025 21:33:16 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 709A168AEB1; Thu, 1 May 2025 00:33:12 +0300 (EEST) Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 570DC687C17 for ; Thu, 1 May 2025 00:33:06 +0300 (EEST) Received: by mail-wm1-f41.google.com with SMTP id 5b1f17b1804b1-43ed8d32a95so2605895e9.3 for ; Wed, 30 Apr 2025 14:33:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jkqxz-net.20230601.gappssmtp.com; s=20230601; t=1746048785; x=1746653585; darn=ffmpeg.org; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=3B4Ctw0aqbHExvzjLCxzwoL0CK9SJ+e7ZZCkin9FLBM=; b=F2CXQuFv7wMP98x64GhUZKhgudb7JXgohzJ6HPuWVj1NnPQLqlTEfw9Z6+gY1XvWbg lCc+QrBLU+C+DH952U/OpdkIbg7O95hP3s6oVJ8h7tNW/41xmuFMlouzubhHzhz0WKFl 25yJhAFR+jWHfuW6fwduq+z04UR3zYdZPu135BifGID7rMw8ORR/0w+tzVweIW56yxyf R5cYwZYLoU84LQz+AhSi1+5AMGPxZS++U/iNWW6rPei4bdWBFSNzq0nPpeDX7J8+HML1 gLOrx5qD7rD1wT/mniymlq4K1lFrWuFP3C5GPJ8NIWWVcqC0mESzndAFu6abKEAa3f3i 8igg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746048785; x=1746653585; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=3B4Ctw0aqbHExvzjLCxzwoL0CK9SJ+e7ZZCkin9FLBM=; b=frtr7/lSjpqh8EDSEUw0TNgyvo3zCi240bwhN3jr9J64W81OQ6jnVeteAUiR1fHEPo 3vlZDvDX3kxY9lWjG2USdnYnAhbbzBJxL0f8se9ZuRnk9Pm9wluOwKeCbdDQIUfR2hhu 5vlMqEfdpP4EUGkWAmjuvPu/uP+EWRlDfLKZ2b182ibcA3fFUCgz/I5lz2UbXS8nSQgr +z9kvKMazCV4++qb90i+0wX0VNxZEjmo/iw6gPFms6/O6md+5RXRcEGnJ2WPbh9aO/XK yZTs/9cuaNKjYKCZ0YWHhgO13vDig7G0PE8fl/B6pwEMm4VGrChxR1WK2bOGa5VlRrj/ vgXA== X-Gm-Message-State: AOJu0YzlvQuJaUAlhBaZtUVXhC2g8WdNbmyO1fZjDeNN1ziOa2jxrw7a ZXYKzMUwShLWVVrhxla7M3YFF9hZC1vHzubV2aLUo3XJGihTT7PSTP4AG1667RbyouQ8hRSr9/Y FKg2i2Q== X-Gm-Gg: ASbGncszuut/rnOONK5072HrxpgA9Ieih9Drbgi/hh6rpIM1RBz1FPhXCTI7fkGuqmb Z7yezDpJ5IdH5jj5nrLmfHm6mkyoiVvzObgt9g5fkrflKCFI1KnrVvKVubUOw6B2q7EdUPoKzv1 dQqrSQVYyVjZjaMLLdDHsSxRr4MFo5bcwHUYCcvFudaTypi7KrGIb8KVExrzjGdrDP7LFjsPb81 4NradvgElSM9ZBFDMnSkirZSRNLd0ZEXEhb1V9XBXbh8PAixBF32g1QyQqXvZRvyTjJWLLgPxE+ rHd2yFaHadPni6P8sxfLBHD2BMoWiFsEskVsxWZs4+MPnhU9MALS+r0EYfJ2xevkGbAGlUa25CM lnUC29zwXJcMsMg== X-Google-Smtp-Source: AGHT+IGjUNOnn02KSzTZY7cD9ImmJ81+jeOqplfJewdbweD3KvMXszfnJHksIO1g3n8GgeuIxQh2lg== X-Received: by 2002:a05:600c:1d12:b0:43d:2313:7b49 with SMTP id 5b1f17b1804b1-441b7017ff2mr1574195e9.12.1746048785498; Wed, 30 Apr 2025 14:33:05 -0700 (PDT) Received: from [192.168.0.15] (cpc92320-cmbg19-2-0-cust719.5-4.cable.virginm.net. [82.13.66.208]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a073e46517sm18044797f8f.71.2025.04.30.14.33.04 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Apr 2025 14:33:05 -0700 (PDT) Message-ID: <1770fdfc-7434-4928-b504-c64487baa43e@jkqxz.net> Date: Wed, 30 Apr 2025 22:32:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: ffmpeg-devel@ffmpeg.org References: From: Mark Thompson In-Reply-To: Subject: Re: [FFmpeg-devel] [PATCH] avcodec/apv_dsp: Fix left-shift of negative value 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: On 30/04/2025 19:26, Andreas Rheinhardt wrote: > Patch attached. > > - Andreas Hmm, the spec does write exactly this but also defines << as arithmetic left shift of a two's complement representation so it works. Seems fair, LGTM. More generally this line is not robust to extreme values (can integer overflow 32 bits), but the cases which do this are not useful and won't be in real streams (if calculated at full precision they would always be far outside the possible coefficient range from a forward transform, so it takes a crafted encoder to make them). Possibly a pre-clip to a calculated range which ensures it doesn't go too far outside the following clip range is the right answer to avoid the overflow? I will think about this a bit more. Thanks, - Mark _______________________________________________ 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".