Re: [FFmpeg-devel] [PATCH 3/3] lavc/dxv: remove ctx fields that can be derived from texdsp ctxs

[Connor Worley <connorbworley@gmail.com>]

I'm not sure how I would write it in a way that isn't a repetition of the
new definition of ctx->tex_size

On Sun, Jan 28, 2024 at 11:52 PM Andreas Rheinhardt <
andreas.rheinhardt@outlook.com> wrote:

> Connor Worley:
> > Signed-off-by: Connor Worley <connorbworley@gmail.com>
> > ---
> >  libavcodec/dxv.c | 53 ++++++++----------------------------------------
> >  1 file changed, 9 insertions(+), 44 deletions(-)
> >
> > diff --git a/libavcodec/dxv.c b/libavcodec/dxv.c
> > index cae5d8a92f..b29adf8ad9 100644
> > --- a/libavcodec/dxv.c
> > +++ b/libavcodec/dxv.c
> > @@ -39,20 +39,12 @@ typedef struct DXVContext {
> >
> >      uint8_t *tex_data;   // Compressed texture
> >      uint8_t *ctex_data;  // Compressed chroma texture
> > -    int tex_rat;         // Compression ratio
> > -    int tex_step;        // Distance between blocks
> > -    int ctex_step;       // Distance between blocks
> > +
> >      int64_t tex_size;    // Texture size
> >      int64_t ctex_size;   // Chroma texture size
> >
> >      uint8_t *op_data[4]; // Opcodes
> >      int64_t op_size[4];  // Opcodes size
> > -
> > -    int texture_block_w;
> > -    int texture_block_h;
> > -
> > -    int ctexture_block_w;
> > -    int ctexture_block_h;
> >  } DXVContext;
> >
> >  /* This scheme addresses already decoded elements depending on 2-bit
> status:
> > @@ -865,9 +857,6 @@ static int dxv_decode(AVCodecContext *avctx, AVFrame
> *frame,
> >      cavctx.coded_height = avctx->coded_height / 2;
> >      cavctx.coded_width  = avctx->coded_width  / 2;
> >
> > -    ctx->texture_block_h = 4;
> > -    ctx->texture_block_w = 4;
> > -
> >      avctx->pix_fmt = AV_PIX_FMT_RGBA;
> >      avctx->colorspace = AVCOL_SPC_RGB;
> >
> > @@ -878,8 +867,6 @@ static int dxv_decode(AVCodecContext *avctx, AVFrame
> *frame,
> >          texdsp_ctx.tex_funct = ctx->texdsp.dxt1_block;
> >          texdsp_ctx.tex_ratio = 8;
> >          texdsp_ctx.raw_ratio = 16;
> > -        ctx->tex_rat   = 8;
> > -        ctx->tex_step  = 8;
> >          msgcomp = "DXTR1";
> >          msgtext = "DXT1";
> >          break;
> > @@ -888,8 +875,6 @@ static int dxv_decode(AVCodecContext *avctx, AVFrame
> *frame,
> >          texdsp_ctx.tex_funct = ctx->texdsp.dxt5_block;
> >          texdsp_ctx.tex_ratio = 16;
> >          texdsp_ctx.raw_ratio = 16;
> > -        ctx->tex_rat   = 4;
> > -        ctx->tex_step  = 16;
> >          msgcomp = "DXTR5";
> >          msgtext = "DXT5";
> >          break;
> > @@ -901,16 +886,8 @@ static int dxv_decode(AVCodecContext *avctx,
> AVFrame *frame,
> >          ctexdsp_ctx.tex_funct = ctx->texdsp.rgtc1u_gray_block;
> >          ctexdsp_ctx.tex_ratio = 16;
> >          ctexdsp_ctx.raw_ratio = 4;
> > -        ctx->tex_rat   = 8;
> > -        ctx->tex_step  = 32;
> > -        ctx->ctex_step = 16;
> >          msgcomp = "YOCOCG6";
> >          msgtext = "YCG6";
> > -        ctx->ctex_size = avctx->coded_width * avctx->coded_height / 4;
> > -        ctx->texture_block_h = 4;
> > -        ctx->texture_block_w = 16;
> > -        ctx->ctexture_block_h = 4;
> > -        ctx->ctexture_block_w = 4;
> >          avctx->pix_fmt = AV_PIX_FMT_YUV420P;
> >          avctx->colorspace = AVCOL_SPC_YCOCG;
> >          break;
> > @@ -922,16 +899,8 @@ static int dxv_decode(AVCodecContext *avctx,
> AVFrame *frame,
> >          ctexdsp_ctx.tex_funct = ctx->texdsp.rgtc1u_gray_block;
> >          ctexdsp_ctx.tex_ratio = 16;
> >          ctexdsp_ctx.raw_ratio = 4;
> > -        ctx->tex_rat   = 4;
> > -        ctx->tex_step  = 64;
> > -        ctx->ctex_step = 16;
> >          msgcomp = "YAOCOCG10";
> >          msgtext = "YG10";
> > -        ctx->ctex_size = avctx->coded_width * avctx->coded_height / 4;
> > -        ctx->texture_block_h = 4;
> > -        ctx->texture_block_w = 16;
> > -        ctx->ctexture_block_h = 4;
> > -        ctx->ctexture_block_w = 4;
> >          avctx->pix_fmt = AV_PIX_FMT_YUVA420P;
> >          avctx->colorspace = AVCOL_SPC_YCOCG;
> >          break;
> > @@ -956,7 +925,6 @@ static int dxv_decode(AVCodecContext *avctx, AVFrame
> *frame,
> >              texdsp_ctx.tex_funct = ctx->texdsp.dxt5_block;
> >              texdsp_ctx.tex_ratio = 16;
> >              texdsp_ctx.raw_ratio = 16;
> > -            ctx->tex_step  = 16;
> >          } else if (old_type & 0x20 || version_major == 1) {
> >              tag = DXV_FMT_DXT1;
> >              msgtext = "DXT1";
> > @@ -964,12 +932,10 @@ static int dxv_decode(AVCodecContext *avctx,
> AVFrame *frame,
> >              texdsp_ctx.tex_funct = ctx->texdsp.dxt1_block;
> >              texdsp_ctx.tex_ratio = 8;
> >              texdsp_ctx.raw_ratio = 16;
> > -            ctx->tex_step  = 8;
> >          } else {
> >              av_log(avctx, AV_LOG_ERROR, "Unsupported header
> (0x%08"PRIX32")\n.", tag);
> >              return AVERROR_INVALIDDATA;
> >          }
> > -        ctx->tex_rat = 1;
> >          break;
> >      }
> >
> > @@ -985,7 +951,6 @@ static int dxv_decode(AVCodecContext *avctx, AVFrame
> *frame,
> >          /* Encoder copies texture data when compression is not
> advantageous. */
> >          if (bytestream2_get_byte(gbc)) {
> >              msgcomp = "RAW";
> > -            ctx->tex_rat = 1;
> >              decompress_tex = dxv_decompress_raw;
> >          }
> >
> > @@ -1003,14 +968,20 @@ static int dxv_decode(AVCodecContext *avctx,
> AVFrame *frame,
> >          return AVERROR_INVALIDDATA;
> >      }
> >
> > -    ctx->tex_size = avctx->coded_width * avctx->coded_height * 4 /
> ctx->tex_rat;
> > +    ctx->tex_size = avctx->coded_width  / (texdsp_ctx.raw_ratio /
> (avctx->pix_fmt == AV_PIX_FMT_RGBA ? 4 : 1)) *
> > +                    avctx->coded_height / TEXTURE_BLOCK_H *
> > +                    texdsp_ctx.tex_ratio;
> >      ret = av_reallocp(&ctx->tex_data, ctx->tex_size +
> AV_INPUT_BUFFER_PADDING_SIZE);
> >      if (ret < 0)
> >          return ret;
> >
> > -    if (ctx->ctex_size) {
> > +    if (avctx->pix_fmt != AV_PIX_FMT_RGBA) {
> >          int i;
> >
> > +        ctx->ctex_size = cavctx.coded_width  / ctexdsp_ctx.raw_ratio *
> > +                         cavctx.coded_height / TEXTURE_BLOCK_H *
> > +                         ctexdsp_ctx.tex_ratio;
> > +
> >          ctx->op_size[0] = avctx->coded_width * avctx->coded_height / 16;
> >          ctx->op_size[1] = avctx->coded_width * avctx->coded_height / 32;
> >          ctx->op_size[2] = avctx->coded_width * avctx->coded_height / 32;
> > @@ -1030,12 +1001,6 @@ static int dxv_decode(AVCodecContext *avctx,
> AVFrame *frame,
> >      ret = decompress_tex(avctx);
> >      if (ret < 0)
> >          return ret;
> > -    {
> > -        int w_block = avctx->coded_width / ctx->texture_block_w;
> > -        int h_block = avctx->coded_height / ctx->texture_block_h;
> > -        if (w_block * h_block * ctx->tex_step > ctx->tex_size * 8LL)
> > -            return AVERROR_INVALIDDATA;
> > -    }
>
> I am pretty sure that this check has been added due to a fuzzing sample
> with gigantic dimensions. Where is the check for this now?
>
> >
> >      ret = ff_thread_get_buffer(avctx, frame, 0);
> >      if (ret < 0)
>
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-- 
Connor Worley
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