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  • Other interesting software

    13 avril 2011, par

    We don’t claim to be the only ones doing what we do ... and especially not to assert claims to be the best either ... What we do, we just try to do it well and getting better ...
    The following list represents softwares that tend to be more or less as MediaSPIP or that MediaSPIP tries more or less to do the same, whatever ...
    We don’t know them, we didn’t try them, but you can take a peek.
    Videopress
    Website : http://videopress.com/
    License : GNU/GPL v2
    Source code : (...)

  • Pas question de marché, de cloud etc...

    10 avril 2011

    Le vocabulaire utilisé sur ce site essaie d’éviter toute référence à la mode qui fleurit allègrement
    sur le web 2.0 et dans les entreprises qui en vivent.
    Vous êtes donc invité à bannir l’utilisation des termes "Brand", "Cloud", "Marché" etc...
    Notre motivation est avant tout de créer un outil simple, accessible à pour tout le monde, favorisant
    le partage de créations sur Internet et permettant aux auteurs de garder une autonomie optimale.
    Aucun "contrat Gold ou Premium" n’est donc prévu, aucun (...)

  • Le plugin : Podcasts.

    14 juillet 2010, par

    Le problème du podcasting est à nouveau un problème révélateur de la normalisation des transports de données sur Internet.
    Deux formats intéressants existent : Celui développé par Apple, très axé sur l’utilisation d’iTunes dont la SPEC est ici ; Le format "Media RSS Module" qui est plus "libre" notamment soutenu par Yahoo et le logiciel Miro ;
    Types de fichiers supportés dans les flux
    Le format d’Apple n’autorise que les formats suivants dans ses flux : .mp3 audio/mpeg .m4a audio/x-m4a .mp4 (...)

Sur d’autres sites (3938)

  • Is there any open source solution to display a remote stream inside a Hololens2 UWP Vuforia application ?

    19 avril 2023, par T777

    What do we need ?

    


    We are trying to develop an application for quality management in which we show an hologram on a metal part as an assitance marking. (using Hololen2 + Vuforia + ModleTargets) The employee uses an sensor to follow this assitance marking and the data will be analyzed live by a test device. The results are outputed on a screen / are visible at an closed source application of the manufacturer of the test device.

    


    Capturing of the video output :
The current plan is to capture the video stream of the test device via capture card. Add a via mrtk2 videopanel inside the vuforia app and stream the captured video to the Hololens2 using obs or an OpenCV python script for screen recording.

    


    What we have tried so far

    


    1) Sending Raw udp stream
via RMTP and decoding + converting with gstreamer server and writing an own library in Unity for Receiving
Result : Temporary stopped, because receiving the udp streams needs connection/ session management (signalling) frame syncing and agreement on video size, color format, frame rate etc.. and we have no solution.
An own implementation of any of this would have high complexity is consuming a lot of time.

    


    2) Using available protocols that i can find on the web
Actually there are some protocols already developed for session creation and streaming :

    


      

    • HTTP streaming (HLS) (Transport + Session)
    • 


    • RTMP (Transport + Session),
    • 


    • RTP (Transport) + RTPS (Session),
    • 


    • WebRTC : Is possible with different protocol stacks
RTMP/TCP/UDP (Transport) + SDP (standardized format for video paramaters) + ICE (p2p)/ WHIP (http, client-server) / Websocket(client-server) (signaling protocols) that can be used and some good open source streaming servers (gstreamer, mediamtx and srs)
    • 


    


    When using these the video will be encoded typcially with xh264 and need to be decoded on the HoloLens 2. There are APIs to C/C++ native (hardware) decoding libraries like unity-vlc and ffmpeg.NET that needing media library ffmpeg. I could figure out (not tested) that there is an hardware h264 decoder on the HoloLens2 but I have no clue how to access it. Since there I couldnt disvocer any information about HoloLens2 media libraries.

    


    3) Using Unity packages

    


    


    Will be testing other compile options tomorrow..

    


      

    • Mixed Reality WebRTC (https://github.com/microsoft/MixedReality-WebRTC) :
Various protocol support, Microsoft brought Webrtc specifically to HoloLens.
Deprecated, as fas as I can see just support for Hololens1 and ARM32. So i can not evaluate if trying it with this is worth it.
    • 


    


    What are the next options ?

    


      

    • Developing a raw udp streaming library with untiy directly.
    • 


    • Rebuilding the application with visionlib (ARM32) compatible and MixedRealityWebRTC (ARM32)
    • 


    • Porting ffmpeg + API to UWP ?
    • 


    • Also there seem some affords to make WebRTC in general available to UWP platforms : https://github.com/microsoft/winrtc
    • 


    


    The questions

    


      

    • Does Vuforia support ARM32 ?
    • 


    • How to access hardware decoder of Hololens2 via Unity Code ?
    • 


    


  • Subtitling Sierra VMD Files

    1er juin 2016, par Multimedia Mike — Game Hacking

    I was contacted by a game translation hobbyist from Spain (henceforth known as The Translator). He had set his sights on Sierra’s 7-CD Phantasmagoria. This mammoth game was driven by a lot of FMV files and animations that have speech. These require language translation in the form of video subtitling. He’s lucky that he found possibly the one person on the whole internet who has just the right combination of skill, time, and interest to pull this off. And why would I care about helping ? I guess I share a certain camaraderie with game hackers. Don’t act so surprised. You know what kind of stuff I like to work on.

    The FMV format used in this game is VMD, which makes an appearance in numerous Sierra titles. FFmpeg already supports decoding this format. FFmpeg also supports subtitling video. So, ideally, all that’s necessary to support this goal is to add a muxer for the VMD format which can encode raw video and audio, which the format supports. Implement video compression as extra credit.

    The pipeline that I envisioned looks like this :


    VMD Subtitling Process

    VMD Subtitling Process


    “Trivial !” I surmised. I just never learn, do I ?

    The Plan
    So here’s my initial pitch, outlining the work I estimated that I would need to do towards the stated goal :

    1. Create a new file muxer that produces a syntactically valid VMD file with bogus video and audio data. Make sure it works with both FFmpeg’s playback system as well as the proper Phantasmagoria engine.
    2. Create a new video encoder that essentially operates in pass-through mode while correctly building a palette.
    3. Create a new basic encoder for the video frames.

    A big unknown for me was exactly how subtitle handling operates in FFmpeg. Thanks to this project, I now know. I was concerned because I was pretty sure that font rendering entails anti-aliasing which bodes poorly for keeping the palette count under 256 unique colors.

    Computer Science Puzzle
    When pondering how to process the palette, I was excited for the opportunity to exercise actual computer science. FFmpeg converts frames from paletted frames to full RGB frames. Then it needs to convert them back to paletted frames. I had a vague recollection of solving this problem once before when I was experimenting with a new paletted video codec. I seem to recall that I did the palette conversion in a very naive manner. I just used a static 256-element array and processed each RGB pixel of the frame, seeing if the value already occurred in the table (O(n) lookup) and adding it otherwise.

    There are more efficient algorithms, however, such as hash tables and trees. Somewhere along the line, FFmpeg helpfully acquired a rarely-used tree data structure, which was perfect for this project.

    So I was pretty pleased with this optimization. Too bad this wouldn’t survive to the end of the effort.

    Another palette-related challenge was the fact that a group of pictures would be accumulating a new palette but that palette needed to be recorded before the group. Thus, the muxer needed to have extra logic to rewind the file when the video encoder transmitted a palette change.

    Video Compression
    VMD has a few methods in its compression toolbox. It can use interframe differencing, it has some RLE, or it can code a frame raw. It can also use a custom LZ-like format on top of these. For early prototypes, I elected to leave each frame coded raw. After the concept was proved, I implemented the frame differencing.


    VMD frame #1

    VMD frame #2

    VMD frame difference
    Top frame compared with the middle frame yields the bottom frame : red pixels indicate changes

    Encoding only those red dots in between vast runs of unchanged pixels yielded a vast measurable improvement. The next step was to try wiring up FFmpeg’s existing LZ compression facilities to the encoder. This turned out to be implausible since VMD’s LZ variant has nothing to do with anything FFmpeg already provides. Fortunately, the LZ piece is not absolutely required and the frame differencing + RLE provides plenty of compression.

    Subtitling
    I’ve never done anything, multimedia programming-wise, concerning subtitles. I guess all the entertainment I care about has always been in my native tongue. What a good excuse to program outside of my comfort zone !

    First, I needed to know how to access FFmpeg’s subtitling facilities. Fortunately, The Translator did the legwork on this matter so I didn’t have to figure it out.

    However, I intuitively had misgivings about this phase. I had heard that the subtitling process performs anti-aliasing. That means that the image would need to be promoted to a higher colorspace for this phase and that the anti-aliasing process would likely push the color count way past 256. Some quick tests revealed this to be the case, as the running color count would leap by several hundred colors as soon as the palette accounting algorithm encountered a subtitle.

    So I dug into the subtitle subsystem. I discovered that the subtitle library operates by creating a linked list of subtitle bitmaps that the client app must render. The bitmaps are comprised of 8-bit alpha transparency values that must be composited onto the target frame (i.e., 0 = transparent, 255 = 100% opaque). For example, the letter ‘H’ :

                                      (with 00s removed)
    13 F8 41 00 00 00 00 68 E4  |  13 F8 41             68 E4    
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    14 FF DC D0 D0 D0 D0 E4 EC  |  14 FF DC D0 D0 D0 D0 E4 EC
    14 FF 7E 50 50 50 50 9A EC  |  14 FF 7E 50 50 50 50 9A EC
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    14 FF 44 00 00 00 00 6C EC  |  14 FF 44             6C EC
    11 E0 3B 00 00 00 00 5E CE  |  11 E0 3B             5E CE
    

    To get around the color explosion problem, I chose a threshold value and quantized values above and below to 255 and 0, respectively. Further, the process chooses an appropriate color from the existing palette rather than introducing any new colors.

    Muxing Matters
    In order to force VMD into a general purpose media framework, a lot of special information needs to be passed around. Like many paletted codecs, the palette needs to be transmitted from the file demuxer to the video decoder via some side channel. For re-encoding, this also implies that the palette needs to make the trip from the video encoder to the file muxer. As if this wasn’t enough, individual VMD frames have even more data that needs to be ferried between the muxer and codec levels, including frame change boundaries. FFmpeg provides methods to do these things, but I could not always rely on the systems to relay the data in all cases. I was probably doing something wrong ; I accept that. Instead, I just packed all the information at the front of an encoded frame and split it apart in the muxer.

    I could not quite figure out how to get the audio and video muxed correctly. As a result, neither FFmpeg nor the Phantasmagoria engine could replay the files correctly.

    Plan B
    Since I was having so much trouble creating an entirely new VMD file, likely due to numerous unknown bits of the file format, I thought of another angle : re-use the existing VMD file. For this approach, I kept the video encoder and file muxer that I created in the initial phase, but modified the file muxer to emit a special intermediate file. Then, I created a Python tool to repackage the original VMD file using compressed video data in the intermediate file.

    For this phase, I also implemented a command line switch for FFmpeg to disable subtitle blending, to make the feature feel like less of an unofficial hack, as though this nonsense would ever have a chance of being incorporated upstream.

    At this point, I was seeing some success with the complete, albeit roundabout, subtitling process. I constructed a subtitle file using “Spanish I Learned From Mexican Telenovelas” and the frames turned out fairly readable :


    Le puso los cuernos a él

    “she cheated on him”


    es un desgraciado

    “he’s a scumbag” … these random subtitles could fit surprisingly well !


    The few files that I tested appeared to work fine. But then I handed off my work to The Translator and he immediately found a bunch of problems. According to my notes, the problems mostly took the form of flashing, solid color frames. Further, I found tiny, mostly imperceptible flaws in my RLE compressor, usually only detectable by running strict comparison tools ; but I wasn’t satisfied.

    At this point, I think I attempted to just encode the entire palette at the front of each frame, as allowed by the format, but that did not seem to fix any problems. My notes are not completely clear on this matter (likely because I was still trying to figure out the exact problem), but I think it had to do with FFmpeg inserting extra video frames in order to even out gaps in the video framerate.

    Sigh, Plan C
    At this point, I was getting tired of trying to force FFmpeg to do this. So I decided to minimize its involvement using lessons learned up to this point.

    The next pitch :

    1. Create a new C program that can open an existing VMD file and output an identical VMD file. I know this sounds easy, but the specific method of copying entails interpreting individual parts of the file and writing those individual parts to the new file. This is in preparation for…
    2. Import the VMD video decoder functions directly into the program to decode the individual video frames and re-encode them, replacing the video frames as the file is rewritten.
    3. Wire up the subtitle system. During the adventure to disable subtitle blending, I accidentally learned enough about interfacing to the subtitle library to just invoke it directly.
    4. Rewrite the RLE method so that it is 100% correct.

    Off to work I went. That part about lifting the existing VMD decoder functions out of their libavcodec nest turned out to not be that straightforward. As an alternative, I modified the decoder to dump the raw frames to an intermediate file. In doing so, I think I was able to avoid the issue of the duplicated frames that plagued the previous efforts.

    Also, remember how I was really pleased with the palette conversion technique in which I was able to leverage computer science big-O theory ? By this stage, I had no reason to convert the paletted video to RGB in the first place ; all of the decoding, subtitling and re-encoding operates in the paletted colorspace.

    This approach seemed to work pretty well. The final program is subtitle-vmd.c. The process is still a little weird. The modifications in my own FFmpeg fork are necessary to create an intermediate file that the new C tool can operate with.

    Next Steps
    The Translator has found some assorted bugs and corner cases that still need to be ironed out. Further, for extra credit, I need find the change windows for each frame to improve compression just a little more. I don’t think I will be trying for LZ compression, though.

    However, almost as soon as I had this whole system working, The Translator informed me that there is another, different movie format in play in the Phantasmagoria engine called ROBOT, with an extension of RBT. Fortunately, enough of the algorithms have been reverse engineered and re-implemented in ScummVM that I was able to sort out enough details for another subtitling project. That will be the subject of a future post.

    See Also :

  • How to run a bat file when clicking a button in an electron + react application ?

    12 novembre 2020, par Артем

    I am using Windows 7
    
I want to write a windows app using electron + react.
    
The essence of the application is to run bat files.
    
Bat files will execute their script.
    
In this case, I have already written baht files, they work with the FFMPEG.
    
I like FFMPEG and I would like to make it easy to use on Windows with such an application.
    
At this stage, I have two folders Your_files and Result, next to these folders are ready-made baht files and ffmpeg.exe.

    


      

    1. In the folder Your_files I put the files to convert.
    2. 


    3. I click on the desired baht file, it converts.
    4. 


    5. I take the finished files from the Result folder.
    6. 


    


    I would like to write a nice application now.
    
There will be one window with buttons in the CMD style - minimalism. On the buttons, the labels are similar (mp4 - mkv) and others.
    
I also plan to place two folders Your_files and Result next to the application.
    
The principle is the same, only here is a beautiful visual interface with buttons for the place of many baht files.
    
It will be easier to visually choose what you need.
    
The crux of the question : How to launch a baht file when you click on a button in the application ?
    Perhaps you have some ideas on how to implement this even better .. I welcome your suggestions with a detailed description.
    
------------------------
    
P.S. I originally planned the following... But I decided to abandon this implementation. ))
    
I recorded a cycle in a baht file.
    
The cycle was launched in the bat file mshta.exe with HTML layout (visual interface). lol
    
Received the value of a variable, which he entered in the visual interface of the mshta.exe window.
    
The variable returned to the loop and the baht file was executed.
    
But I don't think this is the best approach. Use a similar hybrid.
    
Take a look at this for fun.

    


    &#xA;&#xA;&#xA;&#xA;&#xA;&#xA;    &#xA;    &#xA;    &#xA;    &#xA;    <code class="echappe-js">&lt;script type=&quot;text/javascript&quot;&gt;&amp;#xA;        function myFunction() {&amp;#xA;            var copyText = document.getElementById(&quot;myInput&quot;);&amp;#xA;            copyText.select();&amp;#xA;            document.execCommand(&quot;copy&quot;);&amp;#xA;        }&amp;#xA;    &lt;/script&gt;&#xA;&#xA;&#xA;&#xA;    &lt;script language=&amp;#x27;javascript&amp;#x27;&gt;&amp;#xA;        window.resizeTo(800, 300);&amp;#xA;&amp;#xA;        function entperPressed(e) {&amp;#xA;            if (e.keyCode == 13) {&amp;#xA;                pipePass();&amp;#xA;            }&amp;#xA;        }&amp;#xA;&amp;#xA;        function pipePass() {&amp;#xA;            var pass = document.getElementById(&amp;#x27;pass&amp;#x27;).value;&amp;#xA;            var fso = new ActiveXObject(&amp;#x27;Scripting.FileSystemObject&amp;#x27;).GetStandardStream(1);&amp;#xA;            close(fso.Write(pass));&amp;#xA;&amp;#xA;        }&amp;#xA;    &lt;/script&gt;&#xA;    

    Enter time of frame. Введите время кадра

    &#xA;

    hh:mm:ss.mss – 00:00:00.000

    &#xA;

    (colons can be omitted as well as milliseconds)

    &#xA;

    (двоеточия при вводе можно опустить как и миллисекунды)

    &#xA;

    &#xA; &#xA;

    &#xA;

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    &#xA; &#xA;

    &#xA;&#xA;&#xA;&#xA;

    &#xA;

    Photo

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