[Ffmpeg-devel] tracing GOP start code

[Micro Mysore]

Hello,

I want to find the method used to determine the start of GOP .. 

I cud find this code in libavcodec/mpeg12.c

00246 /* put sequence header if needed */
00247 static void mpeg1_encode_sequence_header(MpegEncContext *s)
00248 {
00249         unsigned int vbv_buffer_size;

00259         if (s->current_picture.key_frame) {
00260             AVRational framerate= frame_rate_tab[s->frame_rate_index];

But i cant quite trace where the key_frame was set.

I am trying to find if ffmpeg uses constant length of GOP or if not,
what algorithm it uses to find the scene change.

-mic