[FFmpeg-soc] Bitstream writer from vorbis_enc.c

[Bartlomiej Wolowiec]

Sunday 24 August 2008 05:00:43 Michael Niedermayer napisał(a):
> On Sun, Aug 24, 2008 at 01:56:10AM +0200, Bartlomiej Wolowiec wrote:
> > Saturday 23 August 2008 03:33:27 Michael Niedermayer napisał(a):
> > > On Sat, Aug 23, 2008 at 12:31:48AM +0200, Bartlomiej Wolowiec wrote:
> > > > In nellymoserenc.c is a duplicate of bitstream writer code from
> > > > vorbis_enc.c. How should I remove this duplicate? Add to bitstream.h
> > > > this code and make activation by BITSTREAM_WRITER_LE available?
> > >
> > > The put_bits code in vorbis_enc.c is extreemly poorly written and it
> > > needs be cleaned up before it can be used by another encoder.
> > > Actually i wonder how this code managed to get into svn ...
> > >
> > > [...]
> >
> > I tried to wrote patch to bitstream.h. I hope that it's better than
> > previous code.
> >
> > --
> > Bartlomiej Wolowiec
> >
> > Index: bitstream.h
> > ===================================================================
> > --- bitstream.h	(wersja 14909)
> > +++ bitstream.h	(kopia robocza)
> > @@ -123,6 +123,7 @@
> >  #ifdef ALT_BITSTREAM_WRITER
> >      align_put_bits(s);
> >  #else
> > +#ifndef BITSTREAM_WRITER_LE
> >      s->bit_buf<<= s->bit_left;
> >      while (s->bit_left < 32) {
> >          /* XXX: should test end of buffer */
> > @@ -130,6 +131,14 @@
> >          s->bit_buf<<=8;
> >          s->bit_left+=8;
> >      }
> > +#else
> > +    while (s->bit_left < 32) {
> > +        /* XXX: should test end of buffer */
> > +        *s->buf_ptr++=s->bit_buf;
> > +        s->bit_buf>>=8;
> > +        s->bit_left+=8;
> > +    }
> > +#endif
>
> theres some common code between if and else
>
> >      s->bit_left=32;
> >      s->bit_buf=0;
> >  #endif
> > @@ -190,6 +199,7 @@
> >
> >      //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt,
> > bit_buf); /* XXX: optimize */
> > +#ifndef BITSTREAM_WRITER_LE
> >      if (n < bit_left) {
> >          bit_buf = (bit_buf<<n) | value;
> >          bit_left-=n;
> > @@ -210,7 +220,27 @@
> >          bit_left+=32 - n;
> >          bit_buf = value;
> >      }
> > +#else // BITSTREAM_WRITER_LE
> > +    bit_buf |= value << (32 - bit_left);
> > +    if (n >= bit_left) {
> > +#ifdef UNALIGNED_STORES_ARE_BAD
> > +        if (3 & (intptr_t) s->buf_ptr) {
> > +            s->buf_ptr[0] = bit_buf;
> > +            s->buf_ptr[1] = bit_buf >> 8;
> > +            s->buf_ptr[2] = bit_buf >> 16;
> > +            s->buf_ptr[3] = bit_buf >> 24;
> > +        } else
> > +#endif
> > +        *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
> > +        s->buf_ptr+=4;
> >
> >
> > +        //FIXME: value>>32 == value... ?!
>
> value>>32 == undefined
>
> [...]

Ok. Here is improved patch.

-- 
Bartlomiej Wolowiec
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