[FFmpeg-devel] [PATCH 1/2] libavcodec/sanm: clear codec47 diff buffers with specific color

[Manuel Lauss]

Hello,

Ping?

On Fri, Nov 8, 2024 at 12:51 PM Manuel Lauss <manuel.lauss at gmail.com> wrote:
>
> The codec47 header provides colors to use to clear the
> 2 difference buffers. This fixes artifacts (black hair, faces) in
> Curse of Monkey Island "CURSERNG.SAN" video.
>
> Signed-off-by: Manuel Lauss <manuel.lauss at gmail.com>
> ---
>  libavcodec/sanm.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c
> index 936746ace4..fcf6234d8a 100644
> --- a/libavcodec/sanm.c
> +++ b/libavcodec/sanm.c
> @@ -915,13 +915,16 @@ static int old_codec47(SANMVideoContext *ctx, int top,
>      uint8_t *dst   = (uint8_t *)ctx->frm0 + left + top * stride;
>      uint8_t *prev1 = (uint8_t *)ctx->frm1;
>      uint8_t *prev2 = (uint8_t *)ctx->frm2;
> +    uint8_t auxcol[2];
>      int tbl_pos = bytestream2_tell(&ctx->gb);
>      int seq     = bytestream2_get_le16(&ctx->gb);
>      int compr   = bytestream2_get_byte(&ctx->gb);
>      int new_rot = bytestream2_get_byte(&ctx->gb);
>      int skip    = bytestream2_get_byte(&ctx->gb);
>
> -    bytestream2_skip(&ctx->gb, 9);
> +    bytestream2_skip(&ctx->gb, 7);
> +    auxcol[0] = bytestream2_get_byteu(&ctx->gb);
> +    auxcol[1] = bytestream2_get_byteu(&ctx->gb);
>      decoded_size = bytestream2_get_le32(&ctx->gb);
>      bytestream2_skip(&ctx->gb, 8);
>
> @@ -937,8 +940,8 @@ static int old_codec47(SANMVideoContext *ctx, int top,
>      }
>      if (!seq) {
>          ctx->prev_seq = -1;
> -        memset(prev1, 0, ctx->height * stride);
> -        memset(prev2, 0, ctx->height * stride);
> +        memset(prev1, auxcol[0], ctx->height * stride);
> +        memset(prev2, auxcol[1], ctx->height * stride);
>      }
>
>      switch (compr) {
> --
> 2.47.0
>