[FFmpeg-devel] [PATCH] lavf/tiff: add support for YUV deflate

[Michael Niedermayer]

On Tue, Aug 19, 2014 at 01:54:58AM -0300, James Almer wrote:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> Seems to work great with yuv deflate tiff images created with our tiff encoder
> 
>  libavcodec/tiff.c | 71 +++++++++++++++++++++++++++----------------------------
>  1 file changed, 35 insertions(+), 36 deletions(-)
> 
> diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
> index 73bf828..7acfe7b 100644
> --- a/libavcodec/tiff.c
> +++ b/libavcodec/tiff.c
> @@ -283,6 +283,34 @@ static int deinvert_buffer(TiffContext *s, const uint8_t *src, int size)
>      return 0;
>  }
>  
> +static void unpack_yuv(TiffContext *s, AVFrame *p,
> +                       const uint8_t *src, int lnum)
> +{
> +    int i, j, k;
> +    int w       = (s->width - 1) / s->subsampling[0] + 1;
> +    uint8_t *pu = &p->data[1][lnum / s->subsampling[1] * p->linesize[1]];
> +    uint8_t *pv = &p->data[2][lnum / s->subsampling[1] * p->linesize[2]];
> +    if (s->width % s->subsampling[0] || s->height % s->subsampling[1]) {
> +        for (i = 0; i < w; i++) {
> +            for (j = 0; j < s->subsampling[1]; j++)
> +                for (k = 0; k < s->subsampling[0]; k++)
> +                    p->data[0][FFMIN(lnum + j, s->height-1) * p->linesize[0] +
> +                               FFMIN(i * s->subsampling[0] + k, s->width-1)] = *src++;
> +            *pu++ = *src++;
> +            *pv++ = *src++;
> +        }
> +    }else{
> +        for (i = 0; i < w; i++) {
> +            for (j = 0; j < s->subsampling[1]; j++)
> +                for (k = 0; k < s->subsampling[0]; k++)
> +                    p->data[0][(lnum + j) * p->linesize[0] +
> +                               i * s->subsampling[0] + k] = *src++;
> +            *pu++ = *src++;
> +            *pv++ = *src++;
> +        }
> +    }
> +}
> +
>  #if CONFIG_ZLIB
>  static int tiff_uncompress(uint8_t *dst, unsigned long *len, const uint8_t *src,
>                             int size)
> @@ -305,9 +333,9 @@ static int tiff_uncompress(uint8_t *dst, unsigned long *len, const uint8_t *src,
>      return zret == Z_STREAM_END ? Z_OK : zret;
>  }
>  
> -static int tiff_unpack_zlib(TiffContext *s, uint8_t *dst, int stride,
> +static int tiff_unpack_zlib(TiffContext *s, AVFrame *p, uint8_t *dst, int stride,
>                              const uint8_t *src, int size,
> -                            int width, int lines)
> +                            int width, int lines, int strip_start)
>  {
>      uint8_t *zbuf;
>      unsigned long outlen;
> @@ -338,6 +366,10 @@ static int tiff_unpack_zlib(TiffContext *s, uint8_t *dst, int stride,
>          } else {
>              memcpy(dst, src, width);
>          }
> +        if (s->photometric == TIFF_PHOTOMETRIC_YCBCR) {
> +            unpack_yuv(s, p, dst, strip_start + line);
> +            line += s->subsampling[1] - 1;
> +        }

is photometric guranteed to match the pix_fmt ?

iam asking as i dont see that being ensured by the code but i might
be missing something
if they could mismatch, id assume it might crash

[...]
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