Theora/Ogg Example

I've recently been playing with Theora for encoding video. I found few examples for encoding raw video frames, and those I found were more complicated that I wanted. Below you will find my first toe-dip in the Theora realm. It basically generates a spinning dot in the middle of the frame and encodes to video at 10 frames per sec.

Have fun.

#define _FILE_OFFSET_BITS 64

#include <stdio.h>
#include <stdlib.h>
#include <ogg h="">
#include "theora/theora.h"
#include <string.h>
#include <math.h>

static FILE *ogg_fp = NULL;
static ogg_stream_state ogg_os;
static theora_state theora_td;
static theora_info theora_ti;

static int
theora_open(const char *pathname)
{
printf("(%s:%d) out filename: %s\n",__FILE__,__LINE__,pathname);
ogg_packet op;
ogg_page og;
theora_comment tc;

ogg_fp = fopen(pathname, "wb");
if(!ogg_fp) {
  fprintf(stderr, "%s: error: %s\n",
    pathname, "couldn't open output file");
  return 1;
}

if(ogg_stream_init(&ogg_os, rand())) {
  fprintf(stderr, "%s: error: %s\n",
    pathname, "couldn't create ogg stream state");
  return 1;
}

if(theora_encode_init(&theora_td, &theora_ti)) {
  fprintf(stderr, "%s: error: %s\n",
    pathname, "couldn't initialize theora encoding");
  return 1;
}

theora_encode_header(&theora_td, &op);
ogg_stream_packetin(&ogg_os, &op);
if(ogg_stream_pageout(&ogg_os, &og)) {
  fwrite(og.header, og.header_len, 1, ogg_fp);
  fwrite(og.body, og.body_len, 1, ogg_fp);
}

// encode a comment into the packet
theora_comment_init(&tc);
theora_encode_comment(&tc, &op);
ogg_stream_packetin(&ogg_os, &op);
if(ogg_stream_pageout(&ogg_os, &og)) {
  fwrite(og.header, og.header_len, 1, ogg_fp);
  fwrite(og.body, og.body_len, 1, ogg_fp);
}

theora_encode_tables(&theora_td, &op);
ogg_stream_packetin(&ogg_os, &op);
if(ogg_stream_pageout(&ogg_os, &og)) {
  fwrite(og.header, og.header_len, 1, ogg_fp);
  fwrite(og.body, og.body_len, 1, ogg_fp);
}

if(ogg_stream_flush(&ogg_os, &og)) {
  fwrite(og.header, og.header_len, 1, ogg_fp);
  fwrite(og.body, og.body_len, 1, ogg_fp);
}

return 0;
}

static int
theora_write_frame(unsigned long w, unsigned long h, unsigned char *yuv)
{
yuv_buffer yuv_buf;
ogg_packet op;
ogg_page og;

unsigned long yuv_w;
unsigned long yuv_h;

unsigned char *yuv_y;
unsigned char *yuv_u;
unsigned char *yuv_v;

unsigned int x;
unsigned int y;

/* Must hold: yuv_w >= w */
yuv_w = (w + 15) & ~15;

/* Must hold: yuv_h >= h */
yuv_h = (h + 15) & ~15;

yuv_y = malloc(yuv_w * yuv_h);
yuv_u = malloc(yuv_w * yuv_h / 4);
yuv_v = malloc(yuv_w * yuv_h / 4);

yuv_buf.y_width = yuv_w;
yuv_buf.y_height = yuv_h;
yuv_buf.y_stride = yuv_w;
yuv_buf.uv_width = yuv_w >> 1;
yuv_buf.uv_height = yuv_h >> 1;
yuv_buf.uv_stride = yuv_w >> 1;
yuv_buf.y = yuv_y;
yuv_buf.u = yuv_u;
yuv_buf.v = yuv_v;

for(y = 0; y <x =" 0;" y =" 0;" x =" 0;">> 1) + (y >> 1) * (yuv_w >> 1)] = 0;
    yuv_v[(x >> 1) + (y >> 1) * (yuv_w >> 1)] = 0;
  }
}

for(y = 0; y < x =" 0;" y =" 0;" x =" 0;">> 1) + (y >> 1) * (yuv_w >> 1)] =
      yuv[3 * (x + y * w) + 1];
    yuv_v[(x >> 1) + (y >> 1) * (yuv_w >> 1)] =
      yuv[3 * (x + y * w) + 2];
  }
}

if(theora_encode_YUVin(&theora_td, &yuv_buf)) {
  return 1;
}

if(!theora_encode_packetout(&theora_td, 0, &op)) {
  return 1;
}

ogg_stream_packetin(&ogg_os, &op);
if(ogg_stream_pageout(&ogg_os, &og)) {
  fwrite(og.header, og.header_len, 1, ogg_fp);
  fwrite(og.body, og.body_len, 1, ogg_fp);
}

free(yuv_y);
free(yuv_u);
free(yuv_v);

return 0;
}

static void
theora_close(void)
{
ogg_packet op;
ogg_page og;
static int theora_initialized = 0;

if (theora_initialized) {
  theora_encode_packetout(&theora_td, 1, &op);
  if(ogg_stream_pageout(&ogg_os, &og)) {
    fwrite(og.header, og.header_len, 1, ogg_fp);
    fwrite(og.body, og.body_len, 1, ogg_fp);
  }

  theora_info_clear(&theora_ti);
  theora_clear(&theora_td);

  fflush(ogg_fp);
  fclose(ogg_fp);
}

ogg_stream_clear(&ogg_os);
}

int
main(int argc, char *argv[])
{
int c;
int n;
unsigned i;
const char* const outFile="foo.ogg";
const unsigned NumFrames = 512;

const unsigned Width = 640/2;
const unsigned Height = 480/2;
const int video_fps_numerator = 30;
const int video_fps_denominator = 1;
const int video_aspect_numerator = 0;
const int video_aspect_denominator = 0;
const int video_rate = 0;
const int video_quality = 63;
theora_info_init(&theora_ti);

theora_ti.width = ((Width + 15) >>4)<<4; height =" ((Height">>4)<<4; frame_width =" Width;" frame_height =" Height;" offset_x =" 0;" offset_y =" 0;" fps_numerator =" video_fps_numerator;" fps_denominator =" video_fps_denominator;" aspect_numerator =" video_aspect_numerator;" aspect_denominator =" video_aspect_denominator;" colorspace =" OC_CS_UNSPECIFIED;" pixelformat =" OC_PF_420;" target_bitrate =" video_rate;" quality =" video_quality;" dropframes_p =" 0;" quick_p =" 1;" keyframe_auto_p =" 1;" keyframe_frequency =" 64;" keyframe_frequency_force =" 64;" keyframe_data_target_bitrate =" video_rate" keyframe_mindistance =" 8;" noise_sensitivity =" 1;" i="0;" frame="" d="" of="" n="" r="255;" const="" unsigned="" char="" y="(abs(R" 2104="" g="255;" 4130="" b="255;" 802="" 4096="">> 13);
  unsigned char U = (abs(R * -1214 + G * -2384 + B * 3598 + 4096 + 1048576) >> 13);
  unsigned char V = (abs(R * 3598 + G * -3013 + B * -585 + 4096 + 1048576) >> 13);
  // generate a frame with specified color
  {
    unsigned i;
    for(i = 0; i < r =" 0;" g =" 0;" b =" 255;" y =" (abs(R">> 13);
    unsigned char U = (abs(R * -1214 + G * -2384 + B * 3598 + 4096 + 1048576) >> 13);
    unsigned char V = (abs(R * 3598 + G * -3013 + B * -585 + 4096 + 1048576) >> 13);
    const unsigned cX = Width/2;
    const unsigned cY = Height/2;
    const unsigned Radius = 50;
    static double theta = 0.0;
    const unsigned x = Radius * sin(theta) + cX;
    const unsigned y = Radius * cos(theta) + cY;
    const unsigned k=3*(x + (Width*y));
    theta -= 5.0 * 3.14159/180.0;
    yuv[k] = Y;
    yuv[k+1] = G;
    yuv[k+2] = B;
  }

  if(theora_write_frame(Width, Height, yuv)) {
    theora_close();
    exit(1);
  }
}

theora_close();
return 0;
}