Re: [rtcweb] H261/MPEG-1 video quality

Maik Merten <maikmerten@googlemail.com> Thu, 14 November 2013 20:30 UTC

Return-Path: <maikmerten@googlemail.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 034F721F9EED for <rtcweb@ietfa.amsl.com>; Thu, 14 Nov 2013 12:30:03 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.399
X-Spam-Level:
X-Spam-Status: No, score=-2.399 tagged_above=-999 required=5 tests=[AWL=0.200, BAYES_00=-2.599]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ItfUJsiX1nBz for <rtcweb@ietfa.amsl.com>; Thu, 14 Nov 2013 12:30:02 -0800 (PST)
Received: from mail-bk0-x231.google.com (mail-bk0-x231.google.com [IPv6:2a00:1450:4008:c01::231]) by ietfa.amsl.com (Postfix) with ESMTP id 25CD911E8119 for <rtcweb@ietf.org>; Thu, 14 Nov 2013 12:30:01 -0800 (PST)
Received: by mail-bk0-f49.google.com with SMTP id w14so1505598bkz.36 for <rtcweb@ietf.org>; Thu, 14 Nov 2013 12:30:01 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=GMkOaA+xNVohIG5Lr7IDP/S0ckzaSJiCvDOcYoMI7pY=; b=ZTsMs4y/jejP+8NeHWNRRr1luFDvucVITDV/RKHta91FaqjzrUpKQDvbvV9uxYUmDS RWn6JUdyiSo/fJuD5OkJPpE4CiIyX1ldgjz1kRMUI4Jxqa8RWvfoYFZlncQsDxFcJmWH UFZFKEc6z4po7YxajM2hPWrIYVCz3HGaPNy725JYQ2M5Q8Fm7WIrwVgzeNNRjjrku9B7 ttG1xrnPttcxqcGAhgpKCDrJlz0xqzicjux9RtmZn8gj+W7AgclG+AzZ52ulwaMDwMu3 HhVX7DGkExXbu76NwQsmPUUCPYvlQfj6QR5z884+4STntaiA1KvnEBPusIJd/fKg+c6S XRow==
X-Received: by 10.205.23.194 with SMTP id rb2mr685479bkb.112.1384461001083; Thu, 14 Nov 2013 12:30:01 -0800 (PST)
Received: from [192.168.2.101] (dslb-088-078-139-230.pools.arcor-ip.net. [88.78.139.230]) by mx.google.com with ESMTPSA id on10sm4715814bkb.13.2013.11.14.12.29.59 for <rtcweb@ietf.org> (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 14 Nov 2013 12:30:00 -0800 (PST)
Message-ID: <528532C6.1060406@googlemail.com>
Date: Thu, 14 Nov 2013 21:29:58 +0100
From: Maik Merten <maikmerten@googlemail.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0
MIME-Version: 1.0
To: rtcweb@ietf.org
References: <5284AB73.5030505@googlemail.com> <5285209D.7020407@googlemail.com> <CAGgHUiSROwRznKZWD4kjn8Vu7SrUVwOnHN1EJ-PTgR=WQmcxAQ@mail.gmail.com> <CAOJ7v-2najyMhcVNC8r0Sg+8xgkgDwasBSz476zA0BEpi2X5Pg@mail.gmail.com>
In-Reply-To: <CAOJ7v-2najyMhcVNC8r0Sg+8xgkgDwasBSz476zA0BEpi2X5Pg@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [rtcweb] H261/MPEG-1 video quality
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 14 Nov 2013 20:30:03 -0000

Am 14.11.2013 20:59, schrieb Justin Uberti:
> Thanks, this is interesting. Is the ffmpeg 261 encoder limited to
> CIF/QCIF, or can you specify arbitrary sizes?

As far as I know CIF/QCIF is hardcoded into the H.261 bitstream format, 
so there is nothing ffmpeg can do about it. The bitstream format of 
MPEG-1 Part 2 lifts this restriction.


Maik