http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general hourly 1 1901-01-01T00:00+00:00 http://gmane.org/img/gmane-25t.png http://gmane.org http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1709 I wouldn't expect it to affect performance. Ogg encapsulation is fairly cheap, and the memcpy()s it requires will be much faster than writing the data in either form to disk. If your video is small (packets often < 4 KB) writing out a packet at a time may spread the disk access more evenly, if that helps. Have you tried setting TH_ENCCTL_SET_SPLEVEL to 2? In the 1.0 encoder this trades some quality/bitrate for performance, and is intended for constrained realtime applications. -r Ralph Giles 2008-11-30T21:48:59 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1708 _______________________________________________ theora mailing list theora< at >xiph.org http://lists.xiph.org/mailman/listinfo/theora Andrea Fontana 2008-11-30T21:25:46 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1707 The colour representation is described extensively in chapter 4 of http://theora.org/doc/Theora.pdf There are two defined colour spaces and one 'undefined' one. The format specification describes how to do conversion for the two defined colour spaces. For files marked 'undefined' you can of course do what you like. The format supports the full range [0,255] for all three components, but for more accurate conversion of the defined spaces, you can target the typical floor/ceiling levels with Y in [16, 235] and UV in [16,240). HTH, -r Ralph Giles 2008-11-26T20:02:03 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1706 _______________________________________________ theora mailing list theora< at >xiph.org http://lists.xiph.org/mailman/listinfo/theora Andrea Fontana 2008-11-26T08:45:15 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1705 Adobe has created an LLVM based C to Flash VM compiler. Their example code includes the Vorbis library: http://labs.adobe.com/wiki/index.php/Alchemy:Libraries This should make producing a Flash Ogg/Theora player using the Theora reference library a fairly straight forward process. Such a player will never perform as well as native support, but it would be highly valuable along side cortado (Java) as a fallback mechanism. Unfortunately I know next to nothing about flash development and have no particular desire to learn, so I'm not offering to do this work. But I'm sure that some people here do, or know people who do. Someone with the right knowledge has an opportunity here to make a very significant impact in the usability of free formats by developing a drop-in flash based fallback for the HTML5 <video/> and <audio/>. Gregory Maxwell 2008-11-20T18:01:21 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1704 Glad you got it working! -r Ralph Giles 2008-11-20T17:34:31 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1703 The former turned out to be the case. I did not understand that theora_encode_packetout with last_p==1 produces a packet containing a frame. I called it with &ogg_packet pointing to packet from last call to theora_encode_packetout and the function of course returned without changing it because no frame had been supplied to theora in the mean time ... After fixing that the number of frames in the file is correct. Thats ok for me. Thank you. Olaf Till 2008-11-20T08:03:15 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1702 It could be a bug in the encoder, or a bug in mplayer. Without seeing the file, it's hard to say. Theora is a fixed-framerate codec; libtheora expects to be handed regularly spaced frames and encodes what it's given as if that's the case. Sometimes that means the driving encoder needs to do temporal jitter or interpolation if the original source was not fixed framerate. -r Ralph Giles 2008-11-19T19:02:59 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1701 Hi, ogg/theora files produced with libtheora-1.0, according to mplayer, contain one frame more than encoded, and the last two frames in the file are at the same time (correct time of the last encoded frame). Is that normal or maybe a bug or a mistake in encoding? If it should be normal: What is the reason? Can it be prevented? How is the relation of the nominal time of the frames in the file to the time at which the encoded frames were aquired --- is there some interpolation in time? I need to know the real time corresponding to each frame in the file ... Olaf Olaf Till 2008-11-19T10:49:38 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1700 You can embed it in HTML with a compatible browser using: <video src='foo.ogg'></video> In SVG you can also embed it using SVG video in a compatible browser: <svg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink'> <video xlink:href="foo.ogg"/> </svg> If the browser doesn not support video in SVG, but does support it it in HTML, you can use foreignObject: <svg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink'> <foreignObject> <div xmlns="http://www.w3.org/1999/xhtml"> <video src="foo.ogg"/> </div> </foreignObject> </svg> Unfortunately the 'compatible browser' is the issue. Opera supports video in SVG. Firefox does not. Firefox and Opera have experimental HTML video support for Theora. Safari has HTML video support but not built in for Theora, it needs XiphQT plugins. Chris. Chris Double 2008-11-12T22:25:54 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1699 Hi all, A while back I wrote in about wanting a theora promotion video. Having a few lazy minutes left in the day, I decided to do some coding to create a small movie. However, I encountered two problems: - The artwork completely &$< at >(%sses, but then again I'm no artist. - How do you actually embed the movie into a SVG file? Otherwise I'd go for HTML but a working example would be cool. The attached program can be used to create a banner movie. It will scroll the image you give it as the first argument over a smaller image and then use ffmpeg2theora to create a theora movie from the sequence of images. After extracting and installing ffmpeg2theora on your system, running: ./theora_banner.py theora_on_the_move.png Should result in a small movie and a directory filled with images. The movie looks horrible (again, I'm no artist) but the idea should be clear. So if anybody can help me with artwork and a working theora in SVG example, I'd be very pleased to trade for my page of code ;) Greets, Bram ________ Bram Neijt 2008-11-12T18:54:17 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1698 Fixed, attached. I'm not sure this fix is optimal though: if there's no sync point, it sends everything. That's the reason the stream was blocking on skeleton. Tested with libshout's example.c and XMMS. _______________________________________________ theora mailing list theora< at >xiph.org http://lists.xiph.org/mailman/listinfo/theora ogg.k.ogg.k< at >googlemail.com 2008-11-12T11:07:14 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1697 One way potential vulnerabilities can be introduced is if at any point a browser can be used to learn information that otherwise couldn't be learned. The most obvious information that needs to be protected is the contents of files. If I put a file on a server but use some type of protection (such as a firewall or password protection) to only allow alice to read that file, I wouldn't expect other sites that alice visits to be able to read the contents of that file. Do note that this is the case even if the file is static. I.e. the file that I'm only making available to alice might be static but private, such as a company private financial presentation, or it can be dynamic and personalized, such as the contents of my stock portfolio. However more than the exact contents of a file can be sensitive. For example we are considering adding a feature (pointer-events) to firefox that allows you to say that only non-transparent parts of an image should respond to events. This would allow things like precise grabbi Jonas Sicking 2008-11-11T10:49:26 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1696 I did the patch, and I tested with complex streams (video). I did not try to just Vorbis+Skeleton, however. Streams were played by (IIRC) mplayer and xine. I can try it out, but might be some time till I can. ogg.k.ogg.k< at >googlemail.com 2008-11-11T10:02:07 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1695 Great. Thanks for clarifying what's going on, and thanks to Rob for raising the issue with Whatwg. -r Ralph Giles 2008-11-11T07:26:25 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1694 Yes, in Mozilla's work-in-progress implementation, an "error" message will be fired at the media element when the cross-domain access control check is failed. The media element's error field will then be a MediaError object with code MEDIA_ERR_NETWORK_SECURITY. This code/behaviour isn't yet specified in the HTML5 spec, and the exact details may change in future, but there will be some form of notification. Chris P. Chris Pearce 2008-11-11T02:04:29 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1693 I believe it can. I think Chris Pearce, the implementor of the cross domain video restriction patch added something in this regard and will bring it up on the WHATWG. He's on this list and hopefully will comment. Chris. Chris Double 2008-11-10T22:40:37 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1692 There isn't a leak of the 'video' proper unless there are bugs. The canvas tag should be the only way to grab frames and it impliments some gnarly tainting to prevent that. The image grabbing issue would be the same for <img/>, so there is no real point in treating <video/> differently for that purpose. But video isn't quite the same as <img/>, for example Video may contain captioning and it would be VERY useful if JS could get to the captioning. A caption leak is probably worse than a few frames leaked for video which is captioned. Even without captions Video also has more information that can leak (length, for example) than just the width and height of images. Likewise, as mentioned, abusing clients for scanning purposes is an important concern. (Although I do wonder if you can't detect the existence of a video file using some legacy tag that isn't subject to the cross-origin check). On Mon, Nov 10, 2008 at 3:27 AM, Conrad Parker <conrad< at >metadecks.org> wrote: I think we need to know if the client Gregory Maxwell 2008-11-10T15:06:13 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1691 2008/11/10 Ralph Giles <giles< at >xiph.org>: got it. So perhaps a good default (unconfigured) server configuration is to not send out any special Allow header, and then document how to change that appropriately. K. Conrad Parker 2008-11-10T08:27:07 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1690 I can't speak for Robert, but I believe the concern with static video is with leaking the video itself, which has privacy and, in a firewalled environment, information security implications. For example, many webcams have a standard access url. So a malicious page could include javascript which probes ip addresses on the user's lan, downloads and samples the video in the background and uploads it back to the origin. Since those cams might be behind a nat/firewall and aren't publicly addressable, this is a breach of organization- level security through what is effectively a subverted machine. -r Ralph Giles 2008-11-10T06:56:21 http://permalink.gmane.org/gmane.comp.multimedia.ogg.theora.general/1689 Hi, thanks Gregory for the heads-up, and to Robert for the explanation. One issue that I'm not clear on is: at what point does served content contain such information that it introduces vulnerabilities? Is it when it contains personalized content/markup, or javascript? Or is a static video file somehow susceptible to attack? I understand that the client must deny cross-origin loads in order to protect the user. So my question concerns what the default file serving behavior should be. If we specify to allow all access by default then stuff "just works" for the simple case of someone setting up a personal video server which just serves static files, and embedding the content from their existing blog (hosted elsewhere). I guess that what's important about that scenario is that the video files are static, which we can take to mean that: * the content and markup of the video are not personalized for the viewer * no application side-effects occur as a result of retrieving the video My understanding of the Conrad Parker 2008-11-10T05:31:27 Search the mailing list at Gmane query http://search.gmane.org/?group=$group=gmane.comp.multimedia.ogg.theora.general