[Ffmpeg-devel] [FWD] [PATCH] immediate decoding of dvd stills

[Michael Niedermayer]

Hi

On Tue, Nov 28, 2006 at 11:30:54PM +0100, Nico Sabbi wrote:
> Nico Sabbi wrote:
> >Michael Niedermayer wrote:
> >
> >>something like:
> >>
> >>-    if (buf_size == 0) {
> >>+    if (buf_size == 0 || !memcmp(buf, (char[]){0,0,1,BF}, 4) {
> >>        /* special case for last picture */
> >>        if (s2->low_delay==0 && s2->next_picture_ptr) {
> >>
> >>[...]
> >
> >
> >
> >updated
> >
> >-    if (buf_size == 0) {
> >+    if(!memcmp(buf, (char[]){0,0,1,0xB7}, 4))
> >+        endsequence = 1;
> 
> idiot me; patch fixed.
> No regression reported by make test

> Index: libavcodec/mpeg12.c
> ===================================================================
> --- libavcodec/mpeg12.c	(revisione 7167)
> +++ libavcodec/mpeg12.c	(copia locale)
> @@ -3037,6 +3037,12 @@
>                  }
>              }
>          }
> +    }else{
> +        /* look for SEQ_END_CODE at the last data in this buffer*/
> +        /* dvd's won't send the next frame start on still images*/
> +        /* SEQ_END_CODE will have to stay at the beginning of a frame*/
> +        if(state == SEQ_END_CODE)
> +            return i-3;
>      }
>      pc->state= state;
>      return END_NOT_FOUND;
> @@ -3054,9 +3060,11 @@
>      int ret, input_size;
>      AVFrame *picture = data;
>      MpegEncContext *s2 = &s->mpeg_enc_ctx;
> +    int endsequence = 0;
>      dprintf("fill_buffer\n");
>  
> -    if (buf_size == 0) {
> +    endsequence = (buf_size > 3 && !memcmp(buf, (char[]){0,0,1,0xB7}, 4));
> +    if (buf_size == 0 || endsequence) {
>          /* special case for last picture */
>          if (s2->low_delay==0 && s2->next_picture_ptr) {
>              *picture= *(AVFrame*)s2->next_picture_ptr;
> @@ -3064,7 +3072,7 @@
>  
>              *data_size = sizeof(AVFrame);
>          }
> -        return 0;
> +        return endsequence ? 4 : 0;

is there a problem with return buf_size; ?
if not then if (buf_size == 0 || !memcmp(buf, (char[]){0,0,1,0xB7}, 4))
can be used and the code is a little simpler (note if buf_size>0) then
there always need to be at least FF_INPUT_BUFFER_PADDING_SIZE bytes allocated
so no need to check for >= 4

except that patch ok if it works

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is