[FFmpeg-devel] [PATCH v2] avcodec/gifdec: skip data lzw consumed

[Michael Niedermayer]

On Tue, Nov 10, 2015 at 07:45:09PM +0100, Paul B Mahol wrote:
> On 11/10/15, Ni Hui <shuizhuyuanluo at 126.com> wrote:
> > this updated patch fix the return code of avcodec_decode_video2 for gif
> > decoding
> >
> > ff_lzw_decode_tail() now returns the consumed bytes in lzw decompress
> > and gif frame data buffer is skipped properly
> > gifdec is the only user of ff_lzw_decode_tail()
> >
> > my usecase tested and the return code problem got disappered :)
> >
> >
> > ---
> >  libavcodec/gifdec.c | 5 +++--
> >  libavcodec/lzw.c    | 3 ++-
> >  libavcodec/lzw.h    | 2 +-
> >  3 files changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c
> > index 9f2e6eb..20ae903 100644
> > --- a/libavcodec/gifdec.c
> > +++ b/libavcodec/gifdec.c
> > @@ -130,7 +130,7 @@ static void gif_copy_img_rect(const uint32_t *src,
> > uint32_t *dst,
> >  static int gif_read_image(GifState *s, AVFrame *frame)
> >  {
> >      int left, top, width, height, bits_per_pixel, code_size, flags, pw;
> > -    int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size;
> > +    int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size,
> > lzwed_len;
> >      uint32_t *ptr, *pal, *px, *pr, *ptr1;
> >      int ret;
> >      uint8_t *idx;
> > @@ -293,7 +293,8 @@ static int gif_read_image(GifState *s, AVFrame *frame)
> >
> >   decode_tail:
> >      /* read the garbage data until end marker is found */
> > -    ff_lzw_decode_tail(s->lzw);
> > +    lzwed_len = ff_lzw_decode_tail(s->lzw);
> > +    bytestream2_skipu(&s->gb, lzwed_len);
> >
> >      /* Graphic Control Extension's scope is single frame.
> >       * Remove its influence. */
> > diff --git a/libavcodec/lzw.c b/libavcodec/lzw.c
> > index 6832c12..b0b9a34 100644
> > --- a/libavcodec/lzw.c
> > +++ b/libavcodec/lzw.c
> > @@ -93,7 +93,7 @@ static int lzw_get_code(struct LZWState * s)
> >      return c & s->curmask;
> >  }
> >
> > -void ff_lzw_decode_tail(LZWState *p)
> > +int ff_lzw_decode_tail(LZWState *p)
> >  {
> >      struct LZWState *s = (struct LZWState *)p;
> >
> > @@ -104,6 +104,7 @@ void ff_lzw_decode_tail(LZWState *p)
> >          }
> >      }else
> >          bytestream2_skip(&s->gb, bytestream2_get_bytes_left(&s->gb));
> > +    return bytestream2_tell(&s->gb);
> >  }
> >
> >  av_cold void ff_lzw_decode_open(LZWState **p)
> > diff --git a/libavcodec/lzw.h b/libavcodec/lzw.h
> > index 4653c1c..6af8a6b 100644
> > --- a/libavcodec/lzw.h
> > +++ b/libavcodec/lzw.h
> > @@ -47,7 +47,7 @@ void ff_lzw_decode_open(LZWState **p);
> >  void ff_lzw_decode_close(LZWState **p);
> >  int ff_lzw_decode_init(LZWState *s, int csize, const uint8_t *buf, int
> > buf_size, int mode);
> >  int ff_lzw_decode(LZWState *s, uint8_t *buf, int len);
> > -void ff_lzw_decode_tail(LZWState *lzw);
> > +int ff_lzw_decode_tail(LZWState *lzw);
> >
> >  /** LZW encode state */
> >  struct LZWEncodeState;
> > --
> > 2.4.1
> >
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> 
> probably ok

applied

thanks

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

Old school: Use the lowest level language in which you can solve the problem
            conveniently.
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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