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From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 09/12] avcodec/sanm: codec4/5/33/34 decoder
Date: Fri, 14 Mar 2025 01:08:06 +0100
Message-ID: <AS8P250MB074445C7E9131CD0EF200B7F8FD22@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20250313111505.166786-10-manuel.lauss@gmail.com>

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@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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  reply	other threads:[~2025-03-14  0:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-13 11:14 [FFmpeg-devel] [PATCH 00/12] avcodec/sanm: various improvements Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 01/12] avcodec/sanm: better frame size detection for old codecs Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 02/12] avcodec/sanm: disable left/top for fullscreen codecs Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 03/12] avcodec/sanm: FOBJ left/top are signed values Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 04/12] avcodec/sanm: misc fixes Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 05/12] avcodec/sanm: fix codec3 Manuel Lauss
2025-03-13 11:14 ` [FFmpeg-devel] [PATCH 06/12] avcodec/sanm: codec2 support Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 07/12] avcodec/sanm: codec23 decoder Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 08/12] avcodec/sanm: codec21 decoder Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 09/12] avcodec/sanm: codec4/5/33/34 decoder Manuel Lauss
2025-03-14  0:08   ` Andreas Rheinhardt [this message]
2025-03-14  7:26     ` Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 10/12] avcodec/sanm: codec37: reimplement comp4 Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 11/12] avcodec/sanm: change GetByteContext member to pointer Manuel Lauss
2025-03-14 20:31   ` Michael Niedermayer
2025-03-14 20:49     ` Manuel Lauss
2025-03-13 11:15 ` [FFmpeg-devel] [PATCH 12/12] avcodec/sanm: properly implement STOR/FTCH for ANIMv1 Manuel Lauss
2025-03-14  0:05 ` [FFmpeg-devel] [PATCH 00/12] avcodec/sanm: various improvements Michael Niedermayer
2025-03-14  7:07   ` Manuel Lauss
2025-03-14 20:25     ` Michael Niedermayer

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