[Vorbis] Vorbis encoding using JavaScript

[Sergei Steshenko]

>________________________________
> From: Mateusz Wielgos <wielgosm at gmail.com>
>To: vorbis at xiph.org 
>Sent: Wednesday, February 13, 2013 7:41 AM
>Subject: [Vorbis] Vorbis encoding using JavaScript
> 
>
>Hello,
>
>
>First of all, I am a complete newblet to anything dealing with audio (a lot of the vocabulary is still rather mysterious to me). I also don't often program in C so please don't throw too many stones if my workflow is less than ideal. :)
>
>
>I would like to port the vorbis encoder to JavaScript. Instead of porting everything by hand from ground up, which would take who-knows-how-long, I am using a tool called emscripten (https://github.com/kripken/emscripten). From the docs:
>
>
>Emscripten is an LLVM-to-JavaScript compiler. It takes LLVM bitcode - which can be generated from C/C++, using llvm-gcc or clang, or any other language that can be converted into LLVM - and compiles that into JavaScript, which can be run on the web (or anywhere else JavaScript can run).
>
>
>I was able to successfully build libogg, libvorbis and libvorbis examples using this tool and generate valid JavaScript (hopefully working as intended also...).
>
>
>In JavaScript, once I obtain the left and right channel audio data (using W3C web audio api) I pass this data into the JavaScript encoder as command line arguments. This data is then read, each string converted to a float, and the vorbis_analysis_buffer is filled with this "parsed" data. Similarly, I pass the quality as an argument and run vorbis_encode_init_vbr accordingly.
>
>
>One last thing that I pass in is a "state" of a stream - either the beginning, middle, or end so I can handle these cases differently (for example, at the start of the stream I set all necessary headers).
>
>
>The generated file, however, does not seem to be valid and does not play.
>
>
>Could somebody verify that my encoding logic is sound? Here is the C source on GitHub (based on libvorbis encoder_example.c) : https://github.com/mateusz-/vorbisenc.js/blob/master/encoder_example.c
>And, if it helps, here is the corrupted/invalid Ogg file : https://raw.github.com/mateusz-/vorbisenc.js/master/audio.ogg
>
>
>Thank you,
>Mateusz
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>

I am just a user of Ogg/Vorbis, so I can't answer your questions specifically.

Still, have you tested everything in "C" ? I.e. does your https://github.com/mateusz-/vorbisenc.js/blob/master/encoder_example.c work as expected ?

Because if it doesn't, JavaScript has nothing to do with your problem.

Regards,
  Sergei.