[FFmpeg-devel] [PATCH v2 3/3] libavcodec/jpeg2000dec: Support for PPM marker

[Gautam Ramakrishnan]

On Sun, Jul 19, 2020 at 12:05 PM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> On Sat, Jul 18, 2020 at 06:46:22PM +0530, gautamramk at gmail.com wrote:
> > From: Gautam Ramakrishnan <gautamramk at gmail.com>
> >
> > This patch adds support for PPM marker for JPEG2000
> > decoder. It allows the samples p1_03.j2k and p1_05.j2k
> > to be decoded.
> > ---
> >  libavcodec/jpeg2000dec.c | 111 +++++++++++++++++++++++++++++++++++----
> >  1 file changed, 101 insertions(+), 10 deletions(-)
> >
> > diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> > index 5e9e97eb6a..e37f834afe 100644
> > --- a/libavcodec/jpeg2000dec.c
> > +++ b/libavcodec/jpeg2000dec.c
> > @@ -71,6 +71,7 @@ typedef struct Jpeg2000POC {
> >  typedef struct Jpeg2000TilePart {
> >      uint8_t tile_index;                 // Tile index who refers the tile-part
> >      const uint8_t *tp_end;
> > +    GetByteContext header_tpg;          // bit stream of header if PPM header is used
> >      GetByteContext tpg;                 // bit stream in tile-part
> >  } Jpeg2000TilePart;
> >
> > @@ -102,6 +103,13 @@ typedef struct Jpeg2000DecoderContext {
> >      uint8_t         cbps[4];    // bits per sample in particular components
> >      uint8_t         sgnd[4];    // if a component is signed
> >      uint8_t         properties[4];
> > +
> > +    uint8_t         has_ppm;
> > +    uint8_t         *packed_headers; // contains packed headers. Used only along with PPM marker
> > +    int             packed_headers_size;
> > +    GetByteContext  packed_headers_stream;
>
> > +    uint8_t         in_tile_headers;
>
> in_tile_headers could be moved into a seperate patch before the ppm addition
> it could also be used for other things than ppm
Yep, makes sense, I shall change this.
>
>
>
> > +
> >      int             cdx[4], cdy[4];
> >      int             precision;
> >      int             ncomponents;
> > @@ -928,6 +936,31 @@ static int get_plt(Jpeg2000DecoderContext *s, int n)
> >      return 0;
> >  }
> >
> > +static int get_ppm(Jpeg2000DecoderContext *s, int n)
> > +{
> > +    void *new;
> > +
> > +    if (n < 3) {
> > +        av_log(s->avctx, AV_LOG_ERROR, "Invalid length for PPM data.\n");
> > +        return AVERROR_INVALIDDATA;
> > +    }
>
> > +    s->has_ppm = 1;
>
> Is there a reason has_ppm is set before all error checks ?
> this leaves the possibility for has_ppm to be set but get_ppm failing
> it seems more consistant to me to only set it if get_ppm succeeded
I shall change this as well
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> If the United States is serious about tackling the national security threats
> related to an insecure 5G network, it needs to rethink the extent to which it
> values corporate profits and government espionage over security.-Bruce Schneier
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".



-- 
-------------
Gautam |