On Mon, 13 Jan 2025, Manuel Lauss wrote:
codec37 operates on 2 buffers, which must be considered private to
the codec and must therefore not be changed by subsequent FOBJs.
Let codec37 therefore operate on frm1/2 instead of frm0/2, but copy
the decoded image to frm0 where other codecs operate on.
Fixes artifacts encountered in Full Throttle "dazed.san" and also
in a lot of Rebel Assault II gameplay videos: these videos consist of
frames with an initial codec37 FOBJ image to set the stage, and
optional codec1-23 FOBJs overlaid on top of that image.
Signed-off-by: Manuel Lauss <manuel.la...@gmail.com>
---
Applies on top of my previous patch "avcodec/sanm: simplify codec37 subcodec 3/4
path"
libavcodec/sanm.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c
index 51b8a2f54c..5bbfd5de8c 100644
--- a/libavcodec/sanm.c
+++ b/libavcodec/sanm.c
@@ -645,10 +645,13 @@ static int old_codec37(SANMVideoContext *ctx, int top,
ctx->rotate_code = 0;
- if (((seq & 1) || !(flags & 1)) && (compr && compr != 2))
- rotate_bufs(ctx, 1);
+ if (((seq & 1) || !(flags & 1)) && (compr && compr != 2)) {
+ void *tmp = ctx->frm1;
+ ctx->frm1 = ctx->frm2;
+ ctx->frm2 = tmp;
FFSWAP?
Thanks,
Marton
+ }
- dst = ((uint8_t*)ctx->frm0) + left + top * stride;
+ dst = ((uint8_t*)ctx->frm1) + left + top * stride;
prev = ((uint8_t*)ctx->frm2) + left + top * stride;
if (mvoff > 2) {
@@ -662,7 +665,6 @@ static int old_codec37(SANMVideoContext *ctx, int top,
bytestream2_get_buffer(&ctx->gb, dst, width);
dst += stride;
}
- memset(ctx->frm1, 0, ctx->height * stride);
memset(ctx->frm2, 0, ctx->height * stride);
break;
case 1:
@@ -729,7 +731,6 @@ static int old_codec37(SANMVideoContext *ctx, int top,
case 2:
if (rle_decode(ctx, dst, decoded_size))
return AVERROR_INVALIDDATA;
- memset(ctx->frm1, 0, ctx->frm1_size);
memset(ctx->frm2, 0, ctx->frm2_size);
break;
case 3:
@@ -783,6 +784,7 @@ static int old_codec37(SANMVideoContext *ctx, int top,
return AVERROR_PATCHWELCOME;
}
+ memcpy(ctx->frm0, ctx->frm1, ctx->buf_size);
return 0;
}
--
2.47.1
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