[MPlayer-dev-eng] : Re: [PATCH] shared memory stream - part 1

[Ötvös Attila]

2007. augusztus 12. 01.01 dátummal Martin Simmons ezt írta:
> >>>>> On Sat, 11 Aug 2007 23:50:55 +0200, Ötvös Attila said:
> >
> > +    p->shmemmaxsize=0;
> > +    for(i=0;i<p->shmemcount;i++) {               // open shared memory
> > +        if (!open_shmem(shmemids[i],
> > +                &(p->shmems[i].shmid),
> > +                &(p->shmems[i].shmemmaxsize),
> > +                &(p->shmems[i].shmptr),
> > +                &(p->shmem),i)) {
> > +            close_shmem(p->shmemcount,p->shmems);
> > +            free(p->shmems);
> > +            m_struct_free(&stream_opts,opts);
> > +            return STREAM_ERROR;
> > +        }
> > +        if (p->shmems[i].shmemmaxsize>p->shmemmaxsize)
> > +            p->shmemmaxsize=p->shmems[i].shmemmaxsize;
> > +    }
> > +    free(shmemids);
> > +    mp_msg(MSGT_OPEN,MSGL_INFO, "Shared memory stream info:"
> > +        " format=0x%x width=%d
> > height=%d\n",p->shmem.format,p->shmem.width, +        p->shmem.height);
> > +    p->shmemrecno = 0;
> > +    p->shmid = p->shmems[p->shmemrecno].shmid;
> > +    p->shmemmaxsize = p->shmems[p->shmemrecno].shmemmaxsize;
>
> Why set p->shmemmaxsize here after computing it in the loop?

Yes, My mistake:

@@ -452,6 +452,7 @@
             p->shmemmaxsize=p->shmems[i].shmemmaxsize;
     }
     free(shmemids);
+    p->data = malloc(p->shmemmaxsize);
     mp_msg(MSGT_OPEN,MSGL_INFO, "Shared memory stream info:"
         " format=0x%x width=%d height=%d\n",p->shmem.format,p->shmem.width,
         p->shmem.height);
@@ -460,7 +461,6 @@
     p->shmemmaxsize = p->shmems[p->shmemrecno].shmemmaxsize;
     p->shmptr = p->shmems[p->shmemrecno].shmptr;
 
-    p->data = malloc(p->shmemmaxsize);
     *file_format = DEMUXER_TYPE_RAWVIDEO;
     stream->flags = 0;
     stream->sector_size = 2048;


> Also, I'm confused about how the shmem reading in fill_buffer is
> synchronized with the writing in write_buffer.

Now shmem is real time stream (similar TV) therefore don't direct sync from 
writer to reader.
Lather we will make direct sync (with pts and rpts) to new type of shmem:

#define SHMEM_SYNC	1
set_shmem_opts(SHMEM_SYNC, ... )
open_output_stream(...)

Thanks.

Best regard.
Attila