Re: [Cellar] Matroska Elements to support frame side data

Luca Barbato <luca.barbato@libav.org> Mon, 12 November 2018 17:21 UTC

Return-Path: <luca.barbato@libav.org>
X-Original-To: cellar@ietfa.amsl.com
Delivered-To: cellar@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 305D412777C for <cellar@ietfa.amsl.com>; Mon, 12 Nov 2018 09:21:47 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.8
X-Spam-Level:
X-Spam-Status: No, score=-2.8 tagged_above=-999 required=5 tests=[BAYES_05=-0.5, RCVD_IN_DNSWL_MED=-2.3] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6U1-4HsPmLpc for <cellar@ietfa.amsl.com>; Mon, 12 Nov 2018 09:21:45 -0800 (PST)
Received: from smtp.gentoo.org (woodpecker.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 4094212896A for <cellar@ietf.org>; Mon, 12 Nov 2018 09:21:44 -0800 (PST)
Received: from eris.local (dynamic-adsl-84-221-124-174.clienti.tiscali.it [84.221.124.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: lu_zero) by smtp.gentoo.org (Postfix) with ESMTPSA id 97562335CEC for <cellar@ietf.org>; Mon, 12 Nov 2018 17:21:43 +0000 (UTC)
To: cellar@ietf.org
References: <24ED459F-2375-4934-9156-E64BB1A8AC05@dericed.com> <62624df3-77e8-3234-8496-30354570abee@noa-archive.com> <1E9938AC-B503-42A4-B1A9-43345F81B30F@dericed.com> <87r2fz7u01.fsf@bunkus.org> <2c9da243-26b0-6ae5-1fb8-0f0448e8728d@mediaarea.net>
From: Luca Barbato <luca.barbato@libav.org>
Message-ID: <fecdcf10-97d8-c3da-e307-f5d5fbd79898@libav.org>
Date: Mon, 12 Nov 2018 18:21:39 +0100
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:64.0) Gecko/20100101 Thunderbird/64.0
MIME-Version: 1.0
In-Reply-To: <2c9da243-26b0-6ae5-1fb8-0f0448e8728d@mediaarea.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/cellar/SPG4xt1bAFOM3Ca0BJ8awRxuK3A>
Subject: Re: [Cellar] Matroska Elements to support frame side data
X-BeenThere: cellar@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Codec Encoding for LossLess Archiving and Realtime transmission <cellar.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/cellar>, <mailto:cellar-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cellar/>
List-Post: <mailto:cellar@ietf.org>
List-Help: <mailto:cellar-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/cellar>, <mailto:cellar-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 12 Nov 2018 17:21:47 -0000

On 05/11/2018 12:20, Jerome Martinez wrote:
> On 05/11/2018 10:29, Moritz Bunkus wrote:
>> Hey,
>>
>>> In other thoughts on this suggestion, I think it could make it difficult
>>> to easily understand if a file has a particular type of side data. For
>>> instance if only a few Clusters somewhere in the Segment contain a
>>> certain type of side data, it would require parsing every Cluster to 
>>> know
>>> what types of side data are available. This uncertainly wouldn’t be the
>>> same issue if the side data was itself a Track.
>> It's not entirely necessary to use a full track for side data. We can 
>> simply
>> signal the presence of side data in the track headers and refer to it 
>> from
>> the side data in the block groups. This would also mean we only have to
>> store the string identifying the side data type once (in the track 
>> headers)
>> instead of in each block.
> 
> 
> It would permit more efficient storage, but IMO it should be optional 
> only, because if we do real time transcoding to MKV we don't have always 
> all sidecar info. I have in mind some A/V content with ancillary data 
> coming only after few minutes, without any change in A/V part.
> 

This should warrant for a stand alone track maybe?

lu