[FFmpeg-devel] [PATCH] lavc/mjpegdec: fix VA-API MJPEG decoding uninitialized huffman table

[mypopy at gmail.com]

On Mon, Oct 29, 2018 at 6:39 PM Li, Zhong <zhong.li at intel.com> wrote:
>
> > From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> > Of Jun Zhao
> > Sent: Monday, October 29, 2018 6:26 PM
> > To: ffmpeg-devel at ffmpeg.org
> > Cc: Zhao, Jun <jun.zhao at intel.com>; Lin, Decai <decai.lin at intel.com>
> > Subject: [FFmpeg-devel] [PATCH] lavc/mjpegdec: fix VA-API MJPEG decoding
> > uninitialized huffman table
> >
> > From: Jun Zhao <jun.zhao at intel.com>
> >
> > Now VA-API HWAccel MJPEG decoding uninitialized huffman table, it's will
> > lead to the decoding error like"Failed to sync surface 0x5: 23 (internal
> > decoding error)." in iHD open source driver.
> >
> > Signed-off-by: dlin2 <decai.lin at intel.com>
> > Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> > ---
> >  libavcodec/mjpegdec.c |   19 +++++++++++++++++++
> >  1 files changed, 19 insertions(+), 0 deletions(-)
> >
> > diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c index
> > b0cb3ff..89effb6 100644
> > --- a/libavcodec/mjpegdec.c
> > +++ b/libavcodec/mjpegdec.c
> > @@ -75,6 +75,25 @@ static int build_vlc(VLC *vlc, const uint8_t *bits_table,
> > static int build_basic_mjpeg_vlc(MJpegDecodeContext *s)  {
> >      int ret;
> > +    int i;
> > +
> > +    /* initialize default huffman tables */
> > +    for (i = 0; i < 16; i++)
> > +        s->raw_huffman_lengths[0][0][i] =
> > avpriv_mjpeg_bits_dc_luminance[i + 1];
> > +    for (i = 0; i < 12; i++)
> > +        s->raw_huffman_values[0][0][i] = avpriv_mjpeg_val_dc[i];
> > +    for (i = 0; i < 16; i++)
> > +        s->raw_huffman_lengths[0][1][i] =
> > avpriv_mjpeg_bits_dc_chrominance[i + 1];
> > +    for (i = 0; i < 12; i++)
> > +        s->raw_huffman_values[0][1][i] = avpriv_mjpeg_val_dc[i];
> > +    for (i = 0; i < 16; i++)
> > +        s->raw_huffman_lengths[1][0][i] =
> > avpriv_mjpeg_bits_ac_luminance[i + 1];
> > +    for (i = 0; i < 162; i++)
> > +        s->raw_huffman_values[1][0][i] =
> > avpriv_mjpeg_val_ac_luminance[i];
> > +    for (i = 0; i < 16; i++)
> > +        s->raw_huffman_lengths[1][1][i] =
> > avpriv_mjpeg_bits_ac_chrominance[i + 1];
> > +    for (i = 0; i < 162; i++)
> > +        s->raw_huffman_values[1][1][i] =
> > + avpriv_mjpeg_val_ac_chrominance[i];
> >
> >      if ((ret = build_vlc(&s->vlcs[0][0], avpriv_mjpeg_bits_dc_luminance,
> >                           avpriv_mjpeg_val_dc, 12, 0, 0)) < 0)
> > --
> > 1.7.1
>
> Should this be fixed in iHD driver instead of ffmpeg?
No, I don't think driver is a good place to initialize the huffman table.