[theora] etheora

Ribamar Santarosa de Sousa
2007-10-31T21:45:17Z

Hello,

I'm about to release a first version of etheora, a simplified api to
programming theora video encoding/decoding applications with ogg
containers. It uses and encapsulates libtheora + libogg API and
structures, so users need to know very few  ,  about video and data
containers.

An encoding process is made by these steps:

/*a context declaration.*/
etheora_ctx *ec;

/*encoder configuration.*/
etheora_enc_configure(&ec, width, height, ETHEORA_ASPECT_NORMAL,
fopen("output-video.ogg"), fopen("debug_info.txt"));

/*encoder start.*/
etheora_enc_start(&ec);

/*drawing next frame, by puting a r,g,b or y,u,v pixel in (i,j) coordinate*/
etheora_enc_rgb_draw(&ec, i, j, r, g, b) (alternative:
etheora_enc_yuv_draw()),

/*submiting frame to encoding.*/
etheora_enc_nextframe(&ec);

/*submiting last frame to encoding by finishing the process.*/
etheora_enc_finish(&ec);


The decoding process is quite similar.
/*a context declaration.*/
etheora_ctx *ec;

/*decoder configuration.*/
etheora_dec_configure(&ec, fopen("input-video.ogg"),
fopen("debug_info.txt"));

/*decoder start.*/
etheora_dec_start(&ec);

/*reading video data.*/
etheora_get_width(&ec);
etheora_get_heigth(&ec);
etheora_get_fps_numerator(&ec);
etheora_get_fps_denominator(&ec);
etheora_get_aspect_numerator(&ec);
etheora_get_aspect_denominator(&ec);

/*getting next frame by decoding it.*/
etheora_dec_nextframe(&ec);

/*getting frame data, by reading a r,g,b or y,u,v pixel in (i,j) coordinate*/
etheora_dec_rgb_read(&ec, i, j, &r, &g, &b) (alternative:
etheora_dec_yuv_read()),

/* finishing the process.*/
etheora_dec_finish(&ec);

the functions _yuv_ and _rgb_ works transparently with OC_PF_420,
OC_PF_422 and OC_PF_PF_444, having the libtheora version used support
for them or not.


Etheora is documented here:
http://opensvn.csie.org/ribamar/projects/streaming/doc/etheora_documentation.pdf

Etheora code is here:
http://opensvn.csie.org/ribamar/projects/streaming/src/ {etheora is
etheora.c, etheora.h, etheora-int.h}

Etheora still doesn't have audio/speech support. (Although it can get
video data from videos with audio). And uses internally the old
libtheora API.

I'm still deciding where to host definetively the project, having a
project home page, start making real version control, etc. Also I'm
deciding which license to use (probably the same BSD-like as
libtheora). But I'd already like to hear from you opinions, suggests,
corrections (included english corrections), etc.

Thanks,
Ribamar