Recherche avancée

Sur d’autres sites (9364)

• Expanding media capabilities of Win Embedded CE 6.0

  1er décembre 2014, par Simo Erkinheimo

  I have an embedded device with WinCE 6.0 as OS. The manufacturer provides an IDE for 3rd party development to it. The IDE pretty much allows nothing else than

  • .NET 3.5 Compact Framework scripting that’s invoked from various events from the main application
  • Adding files to the device.

  The included mediaplayer seems to be using DirectShow and the OS has media codec only for mpeg-1 encoded video playback. My goal is to to be able to play media encoded with some other codecs as well inside that main application.

  I’ve already managed to use DirectShowNETCF (DirectShow wrapper for .NET Compact Framework) and successfully playback mpeg-1 encoded video.

  I’m totally new with this stuff and I have tons of (stupid) questions. I’ll try to narrow them down :

  • The OS is based on WinCE, but as far as I’ve understood, it’s actually always some customized version of it (via Platform Builder). Only "correct way" of developing anything for it afterwards is to use the SDK the manufacturer usually provides. Right ? In my case, the SDK is extremely limited and tightly integrated into IDE as noted above. However, .NET CF 3.5 is capable for interop so its possible to call native libraries -as long as they are compiled for correct platform.

  • Compiled code is pretty much just instructions for the processor (assembler code) and the compiler chooses the correct instructions based on the target processor setting. Also there’s the PE-header that defines under which platform the program is meant to be run. If I target my "helloworld.exe" (does nothing but returns specific exit code) to x86 and compile it with VC, should it work ?

  • If the PE-header is in fact the problem, is it possible to setup for WINCE without the SDK ? Do I REALLY need the whole SDK for creating a simple executable that uses only base types ? I’m using VS2010, which doesn’t even support smart device dev anymore and I’d hate to downgrade just for testing purposes.

  • Above questions are prequel to my actual idea : Porting ffmpeg/ffdshow for WinCE. This actually already exists, but not targeted nor built for Intel Atom. Comments ?

  • If the native implementation is not possible and I would end up implementing some specific codec with C#...well that would probably be quite a massive task. But having to choose C# over native, could I run into problems with codec performance ? I mean.. is C# THAT much slower ?

  Thank you.

• Media Source Extensions - Identifying when there is no more data

  8 octobre 2015, par galbarm

  I’m creating a fragmented MP4 of a real-time live content with constant 10FPS but occasionally a frame gets dropped before being feed to the MP4 creation process.
  The MP4 is transmitted to the web through a web socket.

  Due to the occasional frames drop, the playback speed of the file is effectively slightly greater than 1x, because the player plays at 10FPS.
  Since this is a live content, after some duration, the player reaches the present time and has no data to play.

  Now, to the MSE issue :
  What seems to happen in Chrome, when the player doesn’t have enough data to continue playing, is that it pauses for 1-2 secs, then plays it very fast, and vice versa. So at this point the user experience becomes very bad.
  The issue was discussed here :
  https://www.w3.org/Bugs/Public/show_bug.cgi?id=28379

  My idea to workaround this, is to identify the state (having no more data), change playback rate to 0.9 for a few seconds to allow some buffering, and then switch back to 1.0.
  The problem is that I couldn’t find a way to identify the state.
  The readystate of the media element seems to always have the value of "HAVE_ENOUGH_DATA" even when the issue starts.

  Does the MSE API exposes a way identify the state that I have described ?

• Cross Platform C# Media API

  22 novembre 2011, par maxfridbe

  I'm trying to define a VideoFile in mono/.net object such that I can call

  var file = new VideoFile(filepath);
  
  file.VideoDuration 

  Is there a library (os or commercial) which will work across platforms mono/.net which can provide information such as VideoDuration. The only though I have had on this currently is to wrap ffmpeg.exe and read the console out-stream.