[FFmpeg-user] I Need Some Help

铁 慕容 edward.guo at hotmail.com
Mon May 9 16:39:03 CEST 2011

Dear Sir or Madam
Many thanks for reading this email. I am a new learner of FFMPEG. When I was reading your code recently, come to a confused problem which appears in <dv.c> and line 327. As I consider the pointer "s->idct_put[0]" points to the "dsp.idct_put" which is initialized in <dsputil.c> line 4180. Then I looked through the code found the function "ff_simple_idct_put" (line 4252) and found it appears in <simple_idct.c> line 371 also <simple_idct.h>. 
Logically, I used it to decode DVCPRO 625i50 file but found the result is not exactly correct. Subsequently I compared the address of "c->idct_put= ff_simple_idct_put" in <dsputil.c> line 4252 and the address in <dv.c> when directly call the "ff_simple_idct_put" in <simple_idct.c>. The interesting thing is they are different functions even though they have the same name. To be more sure, I modified the code "mb->idct_put  = s->idct_put[dct_mode && log2_blocksize == 3];" <dv.c> line 521 into "mb->idct_put  = s->idct_put[0]" and print a message in the function "ff_simple_idct_put" of <simple_idct.c> line 371. As you can imagine, the code never go into there.
So I wonder, 
1. which and how you use the idct method when decoding the DVCPRO 625i50 frame? 
2. After the initilization of  "dsp.idct_put" where maybe modify it?
3. where can I get the correct "ff_simple_idct_put" method except the <simple_idct.c>, when decoding DVCPRO 625i50?
4. what's the pointer "dsp.idct_put" really point to?
Please help me.

Kind Wishes


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