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 9154544C2B for ; Tue, 12 Sep 2023 16:25:24 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 3303468C9AD; Tue, 12 Sep 2023 19:25:22 +0300 (EEST) Received: from w4.tutanota.de (w4.tutanota.de [81.3.6.165]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 698826801F2 for ; Tue, 12 Sep 2023 19:25:15 +0300 (EEST) Received: from tutadb.w10.tutanota.de (unknown [192.168.1.10]) by w4.tutanota.de (Postfix) with ESMTP id EE18F10602D4 for ; Tue, 12 Sep 2023 16:25:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1694535914; 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=LEGuhsjetwJJjk6/ygTIeuHAACkuq6turdPymMlPiSs=; b=UEzp2sEpv0iyH+683XMkOUB/jzPtKd0gsSi6hjxySRUchQ6+X8kJzSKmGGOvnNei RFnEj3lDK0g28+Ik9Q0m3uhjEj0U8Q1r34x5vy4VLovsQCoXGb8wXk7DUnm1+nVDTLg MKWyQZnY5jkK+DlHngkOVvnuCqwdlNQkpD94nfRW3ysDFQmgk90+jzmPbMwCbZvXYNG EOf574A0mLNXYQqQSIvZA2FYmcCAOPnOYAoLq7T73amSqwMaDFGsmQLWxdBnDAq4niM r0frIVbSKNiQzDYdkEPBw2hjHSin+5xNhkk9VTERStjU501b3lmfd8faETHHT5ZpaJC NRFohy2m3A== Date: Tue, 12 Sep 2023 18:25:14 +0200 (CEST) From: Lynne To: FFmpeg development discussions and patches Message-ID: In-Reply-To: References: MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [RFC PATCH 1/3] aacdec: always skip the first 2048 samples if there's no side data 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: Sep 12, 2023, 09:43 by andreas.rheinhardt@outlook.com: > Lynne: > >> For some reason, this was never set, which meant all **raw** AAC in ADTS >> streams, except faac, had extra samples at the start. >> >> Despite this being a standard MDCT-based codec with a frame size of 1024, >> hence a delay of 1024 samples at the start, all major encoders, excluding >> faac and FFmpeg, use 2048 samples of padding. >> >> The FFmpeg encoder will be modified to also output 2048 samples of padding >> at the start, to make it in line with other encoders. >> > > Does this also have actual advantages besides "being in line with other > encoders"? > Not really. I don't have an opinion on this. 1024 is the natural delay of the codec, so maybe it would be best to leave it at that. >> Yes, this leaves FATE pretty sad. Will fix it with the real version of the patch. >> > > Didn't we once guess the number of skip samples like this, only for this > guesswork to be removed intentionally? (This is not a rhetorical > question; I thought it to be true, but I see that there is still code > for faac in decode_fill(); maybe I misremember.) > I don't remember something like that. The faac workaround dates back from 2012 (bfe735b5824c7d10ba42932a17d786db50e3b2d4), and it's only for faac. It's less of a guess, as most encoders to use the FIL extension to signal themselves. _______________________________________________ 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".