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• azure encoding : video track in one .webm file, audio track in a .mp3 separate file, output .mp4 file

  26 avril 2016, par Osama Alshaykh

  In azure, I want to generate a video from two independent files : video track is in a .webm file and audio track is in a .mp3 file. Is this possible ?
  I want to use Azure media services. If not, then FFMPEG could be a solution. correct ?

  Thanks,
  Osama

• Back on the Salty Track

  12 juin 2011, par Multimedia Mike — General

  After I posted about my initial encounter and frustration with Google’s Native Client (NaCl) SDK and took a deep breath, I realized that I achieved an important proof of concept— I successfully played music using the NaCl SDK audio output interface. Then I started taking a closer read through the (C-based set of) header files and realized I might be able to make a go of it after all. I had much better luck this time and managed to create a proper Native Client interface that allows for controlling playback, presenting metadata, and toggling individual voices (a fascinating tool for studying classic game music).

  I haven’t bothered to post the actual plugin because, really, what’s the point ? I started with NaCl SDK 0.3 which requires Chrome 12, which means terribly limited reach, even among Chrome users. At least, that was true when I restarted this little project. Chrome 12 was formally released this past week. Chrome development really does move at breakneck pace.

  Anyway, here is a static screenshot of what the plugin currently looks like :

  
  
  

  Not pretty, but it does the job.

  Dev Journal
  Various notes based on this outing :

  • Portability : I tested my plugin using Chrome 12 on 64-bit Windows, Mac, and Linux. Mac and Linux both work ; Windows does not.
  • Build System : SDK 0.3 is still lacking in its ability to compile .cpp files (instead of .cc files) ; necessary because libgme is C++ using .cpp files. This requires some build system modification.
  • Getting the interfaces : This is where I got tripped up the first time around. get_browser_interface() from their example actually refers to a parameter passed in through the PPP_InitializeModule() function. The SDK’s template generator renames this to get_browser().
  • Debugging : I feel unstoppable once I have a printf() mechanism available to me during development. To that end, console.log() from JavaScript outputs to Chrome’s built-in JavaScript console log while putting printf() statements in the actual NaCl plugin causes the messages to show up in /.xsession-errors on Linux/X.
  • Size Matters : The binaries generated with the NaCl 0.3 SDK are ridiculously huge. The basic "Hello World" example in C compiles to binaries that are 6.7 MB and 7.8 MB for the 32- and 64-bit builds, respectively. This made me apprehensive to build a full version of SaltyGME that contains all the bells and whistles offered by the library. However, all of the GME code compiled into the binary adds very little size. Curiously, the C++ version of "Hello World" only ranges from 1.8-2.0 MB for 32- and 64-bit. Is there some kind of C tax happening here ? Note that running ’strip’ on the resulting .nexe files (they’re ELF files, after all) brings the sizes down into the C++ range, but at the cost of causing them to not work (more specifically, not even load).
  • No Messaging : The NaCl SDK is supposed to have a messaging interface which allows the NaCl plugin to send asynchronous messages up to the hosting page. When I try to instantiate it, I get a NULL. I’m stuck with the alternative of polling from the JavaScript side to, e.g., determine when a song has finished loading via the network.

  That’s all I can think of for now. I may work on this a little more (I’d like to at least see some audio visualization). Maybe Google will enable NaCl per default sometime around Chrome 21 and this program will be ready for prime time by then.

  See Also :

  • My first attempt at this same project

• How do you get ffmpeg to convert a video, parse its thumbnail and then pass it back to Elgg in the file upload function ? [closed]

  22 janvier, par Orange

  I know my question is very specific, but I'm using the social media base (with WAMP) Elgg to create a Flash-based video sharing site for older browsers and computers and I was wondering how does one set up ffmpeg and Elgg in tandem so Elgg gets both a thumbnail and a video converted to FLV from an MP4 file someone uploads from their computer.

  


  I'm using Elgg 1.9 and ffmpeg-20130314.

  


  I couldn't figure out how to inject ffmpeg into Elgg so I tried duplicating the upload form so it had two file upload buttons (second one for thumbnail image) but this broke the site and made a blank undeletable video.