On 1/23/20, Robert Deibel <deibel.rob...@googlemail.com> wrote: > Fix shaking of image when zoom is applied by the zoompan filter. > Resolves ticket https://trac.ffmpeg.org/ticket/4298 > --- > libavfilter/vf_zoompan.c | 93 ++++++++++++++++++++++++++++++---------- > 1 file changed, 70 insertions(+), 23 deletions(-) > > diff --git a/libavfilter/vf_zoompan.c b/libavfilter/vf_zoompan.c > index 59c9b19ec8..4ae8c64cd0 100644 > --- a/libavfilter/vf_zoompan.c > +++ b/libavfilter/vf_zoompan.c > @@ -150,16 +150,30 @@ static int config_output(AVFilterLink *outlink) > return 0; > } > > +/** > + * Scales n to be a multiple of grid_size but minimally 2 * grid_size and > divisable by two. > + * > + * Used to scale the width and height of a frame to fit with the > subsampling grid. > + * @param n The number to be scaled. > + * @param grid_size the size of the grid. > + * @return The scaled number divisable by 2 and minimally 2 * grid_size > + */ > +static int scale_to_grid(int n, uint8_t grid_size){ > + return (((n + (1 << grid_size) * 2) & ~((1 << grid_size) - 1)) + 1) & > ~1; > + > +} > + > static int output_single_frame(AVFilterContext *ctx, AVFrame *in, double > *var_values, int i, > double *zoom, double *dx, double *dy) > { > ZPContext *s = ctx->priv; > AVFilterLink *outlink = ctx->outputs[0]; > int64_t pts = s->frame_count; > - int k, x, y, w, h, ret = 0; > + int k, x, y, crop_x, crop_y, w, h, crop_w, crop_h, overscaled_w, > overscaled_h, ret = 0; > uint8_t *input[4]; > int px[4], py[4]; > AVFrame *out; > + double dw, dh; > > var_values[VAR_PX] = s->x; > var_values[VAR_PY] = s->y; > @@ -173,32 +187,46 @@ static int output_single_frame(AVFilterContext *ctx, > AVFrame *in, double *var_va > > *zoom = av_clipd(*zoom, 1, 10); > var_values[VAR_ZOOM] = *zoom; > - w = in->width * (1.0 / *zoom); > - h = in->height * (1.0 / *zoom); > + > + // Keep track of double variables for correct calculation > + w = dw = (double) in->width * (1.0 / *zoom); > + h = dh = (double) in->height * (1.0 / *zoom); > + > + // width and height with additional pixels from subsampling "grid" > + crop_w = scale_to_grid(w, s->desc->log2_chroma_w); > + crop_h = scale_to_grid(h, s->desc->log2_chroma_h); > > *dx = av_expr_eval(s->x_expr, var_values, NULL); > > - x = *dx = av_clipd(*dx, 0, FFMAX(in->width - w, 0)); > - var_values[VAR_X] = *dx; > - x &= ~((1 << s->desc->log2_chroma_w) - 1); > + crop_x = ceil(av_clipd(*dx - (((double) crop_w - w) / 2.0), 0, > FFMAX(in->width - crop_w, 0))); > + var_values[VAR_X] = *dx = av_clipd(*dx, 0, FFMAX(in->width - w, 0)); > + crop_x &= ~((1 << s->desc->log2_chroma_w) - 1); // Masking > LSBs making coordianate divisible > > *dy = av_expr_eval(s->y_expr, var_values, NULL); > > - y = *dy = av_clipd(*dy, 0, FFMAX(in->height - h, 0)); > - var_values[VAR_Y] = *dy; > - y &= ~((1 << s->desc->log2_chroma_h) - 1); > + crop_y = ceil(av_clipd(*dy - (((double) crop_h - h)/ 2.0), 0, > FFMAX(in->height - crop_h, 0))); > + var_values[VAR_Y] = *dy = av_clipd(*dy, 0, FFMAX(in->height - h, 0)); > + crop_y &= ~((1 << s->desc->log2_chroma_h) - 1); // Masking > LSBs making coordianate divisible > > - out = ff_get_video_buffer(outlink, outlink->w, outlink->h); > + overscaled_w = outlink->w + (crop_w - dw) * *zoom; > + overscaled_h = outlink->h + (crop_h - dh) * *zoom; > + > + out = ff_get_video_buffer(outlink, overscaled_w, overscaled_h); > if (!out) { > ret = AVERROR(ENOMEM); > return ret; > } > > - px[1] = px[2] = AV_CEIL_RSHIFT(x, s->desc->log2_chroma_w); > - px[0] = px[3] = x; > + // Values for crop transform. Channel 1 and 2 are chroma plane, 0 luma > plane, 3 alpha plane > + px[1] = px[2] = AV_CEIL_RSHIFT(crop_x, s->desc->log2_chroma_w); > + px[0] = px[3] = crop_x; > > - py[1] = py[2] = AV_CEIL_RSHIFT(y, s->desc->log2_chroma_h); > - py[0] = py[3] = y; > + py[1] = py[2] = AV_CEIL_RSHIFT(crop_y, s->desc->log2_chroma_h); > + py[0] = py[3] = crop_y; > + > + // Crop data in input using px/py > + for (k = 0; k<4; k++) > + input[k] = in->data[k] + py[k] * in->linesize[k] + px[k]; > > s->sws = sws_alloc_context(); > if (!s->sws) { > @@ -206,21 +234,41 @@ static int output_single_frame(AVFilterContext *ctx, > AVFrame *in, double *var_va > goto error; > } > > - for (k = 0; in->data[k]; k++) > - input[k] = in->data[k] + py[k] * in->linesize[k] + px[k]; > - > - av_opt_set_int(s->sws, "srcw", w, 0); > - av_opt_set_int(s->sws, "srch", h, 0); > + // Set context variables. Used in scaling transform > + av_opt_set_int(s->sws, "srcw", crop_w, 0); > + av_opt_set_int(s->sws, "srch", crop_h, 0); > av_opt_set_int(s->sws, "src_format", in->format, 0); > - av_opt_set_int(s->sws, "dstw", outlink->w, 0); > - av_opt_set_int(s->sws, "dsth", outlink->h, 0); > + av_opt_set_int(s->sws, "dstw", overscaled_w, 0); > + av_opt_set_int(s->sws, "dsth", overscaled_h, 0); > av_opt_set_int(s->sws, "dst_format", outlink->format, 0); > av_opt_set_int(s->sws, "sws_flags", SWS_BICUBIC, 0); > > if ((ret = sws_init_context(s->sws, NULL, NULL)) < 0) > goto error; > > - sws_scale(s->sws, (const uint8_t *const *)&input, in->linesize, 0, h, > out->data, out->linesize); > + // Scale data in input to defined size and copy to out > + sws_scale(s->sws, (const uint8_t *const *)&input, in->linesize, 0, > crop_h, out->data, out->linesize); > + > + > + // Calculate x and y with respect to rounding error. > + *dx = ((crop_w - dw) * *zoom) / (((double) crop_w - dw) / (*dx - > (double) crop_x)); > + x = ceil(av_clipd(*dx, 0, FFMAX(overscaled_w - outlink->w, 0))); > + x &= ~((1 << s->desc->log2_chroma_w) - 1); // Masking LSBs > making coordianate divisible > + > + *dy = ((crop_h - dh) * *zoom) / (((double) crop_h - dh) / (*dy - > (double) crop_y)); > + y = ceil(av_clipd(*dy, 0, FFMAX(overscaled_h - outlink->h, 0))); > + y &= ~((1 << s->desc->log2_chroma_h) - 1); // Masking LSBs > making coordianate divisible > + > + // Values for crop transform. Channel 1 and 2 are chroma plane, 0 luma > plane, 3 alpha plane > + px[1] = px[2] = AV_CEIL_RSHIFT(x, s->desc->log2_chroma_w); > + px[0] = px[3] = x; > + > + py[1] = py[2] = AV_CEIL_RSHIFT(y, s->desc->log2_chroma_h); > + py[0] = py[3] = y; > + > + // Crop data in input using px/py > + for (k = 0; k<4; k++) > + out->data[k] = out->data[k] + py[k] * out->linesize[k] + px[k]; > > out->pts = pts; > s->frame_count++; > @@ -229,7 +277,6 @@ static int output_single_frame(AVFilterContext *ctx, > AVFrame *in, double *var_va > sws_freeContext(s->sws); > s->sws = NULL; > s->current_frame++; > - > if (s->current_frame >= s->nb_frames) { > if (*dx != -1) > s->x = *dx; > -- > 2.25.0 >
Patch have numerous style issues. Please post minimal patch that fix things. Without addition of obvious comments and removal of empty lines. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
