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The Great Big Beautiful Tomorrow
28 octobre 2011, par
Mis à jour : Octobre 2011
Langue : English
Type : Texte
Autres articles (81)
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Ajouter des informations spécifiques aux utilisateurs et autres modifications de comportement liées aux auteurs
12 avril 2011, parLa manière la plus simple d’ajouter des informations aux auteurs est d’installer le plugin Inscription3. Il permet également de modifier certains comportements liés aux utilisateurs (référez-vous à sa documentation pour plus d’informations).
Il est également possible d’ajouter des champs aux auteurs en installant les plugins champs extras 2 et Interface pour champs extras. -
Problèmes fréquents
10 mars 2010, parPHP et safe_mode activé
Une des principales sources de problèmes relève de la configuration de PHP et notamment de l’activation du safe_mode
La solution consiterait à soit désactiver le safe_mode soit placer le script dans un répertoire accessible par apache pour le site -
MediaSPIP 0.1 Beta version
25 avril 2011, parMediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
The zip file provided here only contains the sources of MediaSPIP in its standalone version.
To get a working installation, you must manually install all-software dependencies on the server.
If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...)
Sur d’autres sites (12596)
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Matomo Launches Global Partner Programme to Deepen Local Connections and Champion Ethical Analytics
25 juin, par Matomo Core Team — Press Releases -
ffmpeg and Red5 Issue : Increase in number of ffmpeg simultaneous streams to Red5 resulting in packet loss
30 octobre 2014, par kajarigdI have a screen sharing app written in flex, using which one person can share his screen with another person via Red5 server (Version : 1.0.3). Platform is Windows Server 2008. Now, I want to load test this Red 5 server to find out maximum how many simultaneous screen sharing session it can allow, without any quality compromise. By quality I mean, speed of transmission and no data loss during transmission. I simulated the load using ffmpeg command.
For this, instead of transmitting a live captured screen, I am transmitting (uploading) a FLV file stored in my local to the Red5 server using ffmpeg command. In the receiving client side, I am starting to download (transmitting) this same FLV file after 5 secs since the upload has started. This is working fine when I am running this test for less than 10 pairs of upstreaming-downstreaming sessions. But, when the number is increasing beyond 10, I am observing significant packet loss in transmission.
Here are the commands I am running in a loop. The loop count is the number of streaming pairs.
- upstreaming :
ffmpeg -re -i -f flv -ar 22050 "rtmp://" -report
- downstreaming :
ffmpeg -re -i "rtmp:// live=1" -report
The and are set in such a way, that in the downstream I will download the same uploaded file. "rtmp ://" are the same in both the cases. I am not doing the upstream in record mode, hence, no physical file is getting saved in the server side. When I am analyzing the file I received in the receiving client side, it is a poor quality video due to frame loss. Uploading and downloading machines are two different machines. I ran the test for many hours, repeating the same 10 simultaneous streaming sets. Each set is consistently giving the same results.
What is puzzling me is, this is working fine without any packet loss for less that 10 simultaneous streaming. I searched about it in various forums, but none of the answers were applicable for this scenario. For a while I was thinking that Red5 has limited capacity, but I found many posts saying Red5 can easily scale up to take very big load. Does that mean, the problem is in my configuration ? I am not sure which are to focus on.
An example log snippet :
Lots of missing data at downstream side. For e.g. between frames 101 and 102 there is a difference of 25 sec. On replaying the video there is a stoppage for this much time.In this time gap all the frames are lost.
frame= 101 fps=1.0 q=14.5 size= 2650kB time=00:01:41.00 bitrate= 214.9kbits/s
frame= 102 fps=1.0 q=13.2 size= 2763kB time=00:02:06.00 bitrate= 179.6kbits/sAny help is appreciated !
- upstreaming :
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Simulating MPEG1/2 transmission over a noisy channel [on hold]
17 novembre 2015, par StepTNTThe question may sound out of scope here but this is my last resource.
I need to write a software that does :
- Get an uncompressed video from disk
- Compress it into MPEG-1 or MPEG-2 being able to change quantization matrix, GOP size and/or macroblock size for DCT/motion search
- Apply a repetition code to add redundancy
- Simulate transmission over a noisy channel with given error rate
- Reconstruct the original stream from the repetition code
- Decode the video and compare it with the original one by gathering stats like frame-by-frame difference, file size and stuff like that
This should by done by a nice GUI to show the input and output videos, alongside their frame difference.
Given what I need to do, I can write some requirements :
- An encoder which allows me to change some of the parameters (needed for point 2)
- A language that allows me to work at bit level (needed for points 3 and 5)
- A language that allows me to build a nice GUI using a designer (GUI is not the core of the project so I can’t afford wasting time by writing one)
So far my searches have led to mixed results that are not giving me enough resources to start.
My first find was this MATLAB project which implements MPEG and has some parameters that can be tweaked (like quantization matrix and GOP pattern for example).
The problem here is that I don’t know MATLAB at all, so I have no idea on how to link everything and build a GUI.So the next step was to move to JAVA, and I found a LOT of FFMPEG wrappers, but none seems to allow me to set the parameters that I need. My last try was with Xuggler but the Wiki is down and the documentation does not talk about what I need. Plus, JAVA doesn’t work at bit level so I’d have issues applying the repetition code.
Failing with JAVA led me to C# and DirectShowNet, but the documentation is quite lacking and I don’t know how to start because I didn’t find anything related to setting the parameters that I need using Filters.
The question now is : is there any language/framework/platform that allows me to do what I need without having to deal with pure C/C++ ?
I’d expect a lot of stuff on this matter since we’re talking about well known codecs, still I’m having a hard time finding what I need.