[FFmpeg-devel] [PATCH 09/12] avcodec/sanm: codec4/5/33/34 decoder
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Fri Mar 14 02:08:06 EET 2025
Manuel Lauss:
> This codec works on 4x4 pixel tiles, which can be generated and read
> from the datastream. They're both identical, codec5 misses a tile
> index to skip the current tile.
> Codecs33/34 are the same as 4/5 but with a different tileset generator.
> Used only in Rebel Assault 1.
>
> Signed-off-by: Manuel Lauss <manuel.lauss at gmail.com>
> ---
> libavcodec/sanm.c | 229 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 229 insertions(+)
>
> diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c
> index bf2ec40df4..91c8ba658b 100644
> --- a/libavcodec/sanm.c
> +++ b/libavcodec/sanm.c
> @@ -293,6 +293,8 @@ typedef struct SANMVideoContext {
> int8_t p8x8glyphs[NGLYPHS][64];
> uint8_t c47itbl[0x10000];
> uint8_t c23lut[256];
> + uint8_t c4tbl[2][256][16];
> + uint16_t c4param;
> } SANMVideoContext;
>
> typedef struct SANMFrameHeader {
> @@ -480,6 +482,142 @@ static av_cold int init_buffers(SANMVideoContext *ctx)
> return 0;
> }
>
> +static void codec33_gen_tiles(SANMVideoContext *ctx, int8_t param1)
> +{
> + uint8_t *dst = &(ctx->c4tbl[0][0][0]);
> + int i, j, k, l, m, n, o, p;
> +
> + for (i = 0; i < 8; i++) {
> + for (k = 0; k < 8; k++) {
> + j = i + param1;
> + l = k + param1;
> + p = (j + k) / 2;
> + j = (j + p) / 2;
> + m = l / 2;
> + n = (i + param1);
> + o = (k + param1);
> +
> + *dst++ = p; *dst++ = p; *dst++ = j; *dst++ = n;
> + *dst++ = p; *dst++ = p; *dst++ = j; *dst++ = i;
> + *dst++ = m; *dst++ = m; *dst++ = p; *dst++ = j;
> + *dst++ = l; *dst++ = l; *dst++ = m; *dst++ = p;
> + }
> + }
> +
> + for (i = 0; i < 8; i++) {
> + for (k = 0; k < 8; k++) {
> + j = i + param1;
> + l = k + param1;
> + n = ((j + l) / 2);
> + m = ((l + n) / 2);
> +
> + *dst++ = j; *dst++ = j; *dst++ = j; *dst++ = j;
> + *dst++ = n; *dst++ = n; *dst++ = n; *dst++ = n;
> + *dst++ = m; *dst++ = m; *dst++ = m; *dst++ = m;
> + *dst++ = l; *dst++ = l; *dst++ = l; *dst++ = l;
> + }
> + }
> +
> + for (i = 0; i < 8; i++) {
> + for (k = 0; k < 8; k++) {
> + j = i + param1;
> + l = k + param1;
> + m = (j + l) / 2;
> + n = (j + m) / 2;
> + o = m / 2;
> + p = j & 0xff;
> +
> + *dst++ = p; *dst++ = p; *dst++ = n; *dst++ = m;
> + *dst++ = p; *dst++ = p; *dst++ = n; *dst++ = m;
> + *dst++ = n; *dst++ = n; *dst++ = m; *dst++ = o;
> + *dst++ = m; *dst++ = m; *dst++ = o; *dst++ = l;
> + }
> + }
> +
> + for (i = 0; i < 8; i++) {
> + for (k = 0; k < 8; k++) {
> + j = i + param1;
> + l = k + param1;
> + m = (j + l) / 2;
> + n = m / 2;
> +
> + *dst++ = j; *dst++ = m; *dst++ = n; *dst++ = l;
> + *dst++ = j; *dst++ = m; *dst++ = n; *dst++ = l;
> + *dst++ = j; *dst++ = m; *dst++ = n; *dst++ = l;
> + *dst++ = j; *dst++ = m; *dst++ = n; *dst++ = l;
> + }
> + }
> +}
> +
> +static void codec4_gen_tiles(SANMVideoContext *ctx, uint16_t param1)
> +{
> + uint8_t *dst = &(ctx->c4tbl[0][0][0]);
> + int i, j, k, l, m, n, o;
> +
> + for (i = 1; i < 16; i += 2) {
> + for (k = 0; k < 16; k++) {
> + j = i + param1;
> + l = k + param1;
> + m = (j + l) / 2;
> + n = (j + m) / 2;
> + o = (l + m) / 2;
> + if (j == m || l == m) {
> + *dst++ = l; *dst++ = j; *dst++ = l; *dst++ = j;
> + *dst++ = j; *dst++ = l; *dst++ = j; *dst++ = j;
> + *dst++ = l; *dst++ = j; *dst++ = l; *dst++ = j;
> + *dst++ = l; *dst++ = l; *dst++ = j; *dst++ = l;
> + } else {
> + *dst++ = m; *dst++ = m; *dst++ = n; *dst++ = j;
> + *dst++ = m; *dst++ = m; *dst++ = n; *dst++ = j;
> + *dst++ = o; *dst++ = o; *dst++ = m; *dst++ = n;
> + *dst++ = l; *dst++ = l; *dst++ = o; *dst++ = m;
> + }
> + }
> + }
> +
> + for (i = 0; i < 16; i += 2) {
> + for (k = 0; k < 16; k++) {
> + j = i + param1;
> + l = k + param1;
> + m = (j + l) / 2;
> + n = (j + m) / 2;
> + o = (l + m) / 2;
> + if (m == j || m == l) {
> + *dst++ = j; *dst++ = j; *dst++ = l; *dst++ = j;
> + *dst++ = j; *dst++ = j; *dst++ = j; *dst++ = l;
> + *dst++ = l; *dst++ = j; *dst++ = l; *dst++ = l;
> + *dst++ = j; *dst++ = l; *dst++ = j; *dst++ = l;
> + } else {
> + *dst++ = j; *dst++ = j; *dst++ = n; *dst++ = m;
> + *dst++ = j; *dst++ = j; *dst++ = n; *dst++ = m;
> + *dst++ = n; *dst++ = n; *dst++ = m; *dst++ = o;
> + *dst++ = m; *dst++ = m; *dst++ = o; *dst++ = l;
> + }
> + }
> + }
> +}
> +
> +
> +static int codec4_load_tiles(SANMVideoContext *ctx, uint16_t param2, uint8_t clr)
> +{
> + uint8_t c, *dst = (uint8_t *)&(ctx->c4tbl[1][0][0]);
> + uint32_t loop = param2 * 8;
> +
> + if (param2 > 256)
> + return AVERROR_INVALIDDATA;
> +
> + if (bytestream2_get_bytes_left(&ctx->gb) < loop)
> + return AVERROR_INVALIDDATA;
> +
> + while (loop--) {
> + c = bytestream2_get_byteu(&ctx->gb);
> + *dst++ = (c >> 4) + clr;
> + *dst++ = (c & 0xf) + clr;
> + }
> +
> + return 0;
> +}
> +
> static void rotate_bufs(SANMVideoContext *ctx, int rotate_code)
> {
> if (rotate_code == 2)
> @@ -519,6 +657,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
> if (ctx->subversion < 2)
> ctx->pal[0] = 0xFFU << 24;
> }
> + ctx->c4param = 0xffff;
>
> return 0;
> }
> @@ -532,6 +671,91 @@ static av_cold int decode_end(AVCodecContext *avctx)
> return 0;
> }
>
> +static int old_codec4(SANMVideoContext *ctx, int left, int top, int w, int h,
> + uint8_t param, uint16_t param2, int codec)
> +{
> + const uint16_t p = ctx->pitch;
> + const uint32_t maxpxo = ctx->height * p;
> + uint8_t mask, bits, idx, *gs, *dst = (uint8_t *)ctx->frm0;
> + int i, j, k, l, bit, ret;
> + int32_t pxoff, pxo2;
> +
> + if (ctx->c4param != param) {
> + if (codec > 32)
> + codec33_gen_tiles(ctx, param);
> + else
> + codec4_gen_tiles(ctx, param);
> + ctx->c4param = param;
> + }
> + if (param2 > 0) {
> + ret = codec4_load_tiles(ctx, param2, param);
> + if (ret)
> + return ret;
> + }
> +
> + if (codec > 32)
> + codec -= 29;
> +
> + for (j = 0; j < w; j += 4) {
Why don't you use loop-scope for iterators?
> + mask = bits = 0;
> + for (i = 0; i < h; i += 4) {
> + pxoff = j + left + ((top + i) * p);
> + if (param2 > 0) {
> + if (bits == 0) {
> + if (bytestream2_get_bytes_left(&ctx->gb) < 1)
> + return AVERROR_INVALIDDATA;
> + mask = bytestream2_get_byteu(&ctx->gb);
> + bits = 8;
> + }
> + bit = !!(mask & 0x80);
> + mask <<= 1;
> + bits--;
> + } else {
> + bit = 0;
> + }
> +
> + if (bytestream2_get_bytes_left(&ctx->gb) < 1)
> + return AVERROR_INVALIDDATA;
> + idx = bytestream2_get_byteu(&ctx->gb);
> + if ((bit == 0) && (idx == 0x80) && (codec != 5))
> + continue;
> +
> + gs = &(ctx->c4tbl[bit][idx][0]);
> + pxo2 = pxoff;
> + for (k = 0; k < 4; k++) {
> + for (l = 0; l < 4; l++) {
> + if (pxo2 >= 0 && pxo2 < maxpxo) {
> + *(dst + pxo2) = *gs;
> + }
> + gs++;
> + pxo2++;
> + }
> + pxo2 = pxo2 - 4 + p;
> + }
> +
> + /* smooth top and left block borders with neighbours */
> + if (((pxoff - p + k) < 0) || ((pxoff - p + k) >= maxpxo)
> + || ((pxoff + 3 * p) < 0) || ((pxoff + 3 * p) >= maxpxo)
> + || (i == 0) || (j == 0))
> + continue;
> + if (param & 0x80) {
> + for (k = 0; k < 4; k++)
> + *(dst + pxoff + k) = ((*(dst + pxoff + k) + *(dst + pxoff - p + k)) >> 1) | 0x80;
> + *(dst + pxoff + 1 * p) = (*(dst + pxoff + 1 * p) + *(dst + pxoff + 1 * p - 1)) >> 1 | 0x80;
> + *(dst + pxoff + 2 * p) = (*(dst + pxoff + 2 * p) + *(dst + pxoff + 2 * p - 1)) >> 1 | 0x80;
> + *(dst + pxoff + 3 * p) = (*(dst + pxoff + 3 * p) + *(dst + pxoff + 3 * p - 1)) >> 1 | 0x80;
> + } else {
> + for (k = 0; k < 4; k++)
> + *(dst + pxoff + k) = ((*(dst + pxoff + k) + *(dst + pxoff - p + k)) >> 1) & 0x7f;
> + *(dst + pxoff + 1 * p) = (*(dst + pxoff + 1 * p) + *(dst + pxoff + 1 * p - 1)) >> 1;
> + *(dst + pxoff + 2 * p) = (*(dst + pxoff + 2 * p) + *(dst + pxoff + 2 * p - 1)) >> 1;
> + *(dst + pxoff + 3 * p) = (*(dst + pxoff + 3 * p) + *(dst + pxoff + 3 * p - 1)) >> 1;
> + }
> + }
> + }
> + return 0;
> +}
> +
> static int rle_decode(SANMVideoContext *ctx, uint8_t *dst, const int out_size)
> {
> int opcode, color, run_len, left = out_size;
> @@ -1427,6 +1651,11 @@ static int process_frame_obj(SANMVideoContext *ctx)
> return old_codec1(ctx, top, left, w, h, codec == 3);
> case 2:
> return old_codec2(ctx, top, left, w, h);
> + case 4:
> + case 5:
> + case 33:
> + case 34:
> + return old_codec4(ctx, top, left, w, h, param, parm2, codec);
> case 21:
> return old_codec21(ctx, top, left, w, h);
> case 23:
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