@@ -291,6 +291,7 @@ typedef struct SANMVideoContext {
int8_t p4x4glyphs[NGLYPHS][16];
int8_t p8x8glyphs[NGLYPHS][64];
+ uint8_t c47itbl[0x10000];
} SANMVideoContext;
typedef struct SANMFrameHeader {
@@ -856,6 +857,55 @@ static int process_block(SANMVideoContext *ctx, uint8_t *dst, uint8_t *prev1,
return 0;
}
+static void codec47_read_interptable(SANMVideoContext *ctx)
+{
+ uint8_t *p1, *p2, *itbl = ctx->c47itbl;
+ int i, j;
+
+ for (i = 0; i < 256; i++) {
+ p1 = p2 = itbl + i;
+ for (j = 256 - i; j; j--) {
+ *p1 = *p2 = bytestream2_get_byte(&ctx->gb);
+ p1 += 1;
+ p2 += 256;
+ }
+ itbl += 256;
+ }
+}
+
+static void codec47_comp1(SANMVideoContext *ctx, uint8_t *dst_in, int width,
+ int height, ptrdiff_t stride)
+{
+ uint8_t p1, *dst, *itbl = ctx->c47itbl;
+ uint16_t px;
+ int i, j;
+
+ dst = dst_in + stride;
+ for (i = 0; i < height; i += 2) {
+ p1 = bytestream2_get_byte(&ctx->gb);
+ *dst++ = p1;
+ *dst++ = p1;
+ px = p1;
+ for (j = 2; j < width; j += 2) {
+ p1 = bytestream2_get_byte(&ctx->gb);
+ px = (px << 8) | p1;
+ *dst++ = itbl[px];
+ *dst++ = p1;
+ }
+ dst += stride;
+ }
+
+ memcpy(dst_in, dst_in + stride, width);
+ dst = dst_in + stride + stride;
+ for (i = 2; i < height - 1; i += 2) {
+ for (j = 0; j < width; j++) {
+ px = (*(dst - stride) << 8) | *(dst + stride);
+ *dst++ = itbl[px];
+ }
+ dst += stride;
+ }
+}
+
static int old_codec47(SANMVideoContext *ctx, int top,
int left, int width, int height)
{
@@ -880,8 +930,11 @@ static int old_codec47(SANMVideoContext *ctx, int top,
av_log(ctx->avctx, AV_LOG_WARNING, "Decoded size is too large.\n");
}
- if (skip & 1)
- bytestream2_skip(&ctx->gb, 0x8080);
+ if (skip & 1) {
+ if (bytestream2_get_bytes_left(&ctx->gb) < 0x8080)
+ return AVERROR_INVALIDDATA;
+ codec47_read_interptable(ctx);
+ }
if (!seq) {
ctx->prev_seq = -1;
memset(prev1, 0, ctx->height * stride);
@@ -900,15 +953,7 @@ static int old_codec47(SANMVideoContext *ctx, int top,
case 1:
if (bytestream2_get_bytes_left(&ctx->gb) < ((width + 1) >> 1) * ((height + 1) >> 1))
return AVERROR_INVALIDDATA;
- for (j = 0; j < height; j += 2) {
- for (i = 0; i < width; i += 2) {
- dst[i] =
- dst[i + 1] =
- dst[stride + i] =
- dst[stride + i + 1] = bytestream2_get_byteu(&ctx->gb);
- }
- dst += stride * 2;
- }
+ codec47_comp1(ctx, dst, width, height, stride);
break;
case 2:
if (seq == ctx->prev_seq + 1) {
Some codec47 frames come with an interpolation table: Combining 2 adjacent pixels into a 16bit value, this value can then be used as index into the interpolation table to get a new pixel value. This is used for subcodec 1, which encodes a key- frame at half width and height, and makes these frame less blocky appearing. Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com> --- libavcodec/sanm.c | 67 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 56 insertions(+), 11 deletions(-)