[FFmpeg-devel] [PATCH 2/4] Implement ocv_dilate libopencv filter wrapper.

[Stefano Sabatini]

On date Sunday 2010-09-12 13:07:45 +0200, Michael Niedermayer encoded:
> On Sat, Sep 11, 2010 at 03:59:18PM +0200, Stefano Sabatini wrote:
> > ---
> >  configure                  |    1 +
> >  libavfilter/Makefile       |    1 +
> >  libavfilter/allfilters.c   |    1 +
> >  libavfilter/vf_libopencv.c |  158 ++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 161 insertions(+), 0 deletions(-)
> > 
> > diff --git a/configure b/configure
> > index 26db167..9453fc9 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1394,6 +1394,7 @@ udp_protocol_deps="network"
> >  
> >  # filters
> >  ocv_smooth_filter_deps="libopencv"
> > +ocv_dilate_filter_deps="libopencv"
> >  
> >  # libraries
> >  avdevice_deps="avcodec avformat"
> > diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> > index a15c3f1..394b674 100644
> > --- a/libavfilter/Makefile
> > +++ b/libavfilter/Makefile
> > @@ -23,6 +23,7 @@ OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o
> >  OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
> >  OBJS-$(CONFIG_NOFORMAT_FILTER)               += vf_format.o
> >  OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
> > +OBJS-$(CONFIG_OCV_DILATE_FILTER)             += vf_libopencv.o
> >  OBJS-$(CONFIG_OCV_SMOOTH_FILTER)             += vf_libopencv.o
> >  OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
> >  OBJS-$(CONFIG_PIXDESCTEST_FILTER)            += vf_pixdesctest.o
> > diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> > index fb84968..da1fedb 100644
> > --- a/libavfilter/allfilters.c
> > +++ b/libavfilter/allfilters.c
> > @@ -43,6 +43,7 @@ void avfilter_register_all(void)
> >      REGISTER_FILTER (HFLIP,       hflip,       vf);
> >      REGISTER_FILTER (NOFORMAT,    noformat,    vf);
> >      REGISTER_FILTER (NULL,        null,        vf);
> > +    REGISTER_FILTER (OCV_DILATE,  ocv_dilate,  vf);
> >      REGISTER_FILTER (OCV_SMOOTH,  ocv_smooth,  vf);
> >      REGISTER_FILTER (PAD,         pad,         vf);
> >      REGISTER_FILTER (PIXDESCTEST, pixdesctest, vf);
> > diff --git a/libavfilter/vf_libopencv.c b/libavfilter/vf_libopencv.c
> > index 63d5b61..6c535f0 100644
> > --- a/libavfilter/vf_libopencv.c
> > +++ b/libavfilter/vf_libopencv.c
> > @@ -63,6 +63,164 @@ static int query_formats(AVFilterContext *ctx)
> >  
> >  static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { }
> >  
> > +static int read_shape_from_file(int *cols, int *rows, int **values, const char *filename, void *log_ctx)
> > +{
> > +    char *p, *buf;
> > +    size_t size;
> > +    int i, j, w;
> > +    FILE *f = fopen(filename, "rb");
> > +    char *line;
> > +
> > +    *cols = *rows = 0;
> > +
> > +    if (!f) {
> > +        av_log(log_ctx, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename, strerror(errno));
> > +        return AVERROR(errno);
> > +    }
> > +    fseek(f, 0, SEEK_END);
> > +    size = ftell(f);
> > +    fseek(f, 0, SEEK_SET);
> > +    buf = av_malloc(size + 1);
> > +    if (!buf) {
> > +        fclose(f);
> > +        return AVERROR(ENOMEM);
> > +    }
> > +    fread(buf, 1, size, f);
> > +    buf[size++] = 0;
> > +    fclose(f);
> > +
> > +    /* prescan file to get the number of lines and the maximum width */
> > +    w = 0;
> > +    for (i = 0; i < size; i++) {
> > +        if (buf[i] == '\n') {
> > +            (*rows)++;
> > +            *cols = FFMAX(*cols, w); w = 0;
> > +        } else
> > +            w++;
> > +    }
> 
> rows & cols can overflow for large files
> 
> 
> > +    av_log(log_ctx, AV_LOG_DEBUG, "rows:%d cols:%d\n", *rows, *cols);
> > +
> > +    if (!(*values = av_mallocz(sizeof(int) * *rows * *cols)))
> > +        return AVERROR(ENOMEM);
> 
> memleak and integer overflow
> 
> and anyway, it should be possible to specify things on the command line and
> not require a file.
> and please explain what this filter does and why it accesses files
> like this

That function get a shape from a file, this is more easily specified
writing the shape right into a file, e.g. by writing:

  *
 ***
*****
 ***
  *

rather than specifing the same thing in cmdline.

[...]

Regards.