[FFmpeg-devel] [PATCH 3/5] avfilter/vf_scale: add optional "ref" input
Niklas Haas
ffmpeg at haasn.xyz
Wed Apr 24 13:51:58 EEST 2024
From: Niklas Haas <git at haasn.dev>
This is automatically enabled if the width/height expressions reference
any ref_* variable. This will ultimately serve as a more principled
replacement for the fundamentally broken scale2ref.
See-Also: https://trac.ffmpeg.org/ticket/10795
---
Changelog | 1 +
doc/filters.texi | 26 ++++++++
libavfilter/vf_scale.c | 132 ++++++++++++++++++++++++++++++++++++++++-
3 files changed, 156 insertions(+), 3 deletions(-)
diff --git a/Changelog b/Changelog
index 8db14f02b4..e821e5ac74 100644
--- a/Changelog
+++ b/Changelog
@@ -7,6 +7,7 @@ version <next>:
- ffmpeg CLI filtergraph chaining
- LC3/LC3plus demuxer and muxer
- pad_vaapi, drawbox_vaapi filters
+- vf_scale supports secondary ref input and framesync options
version 7.0:
diff --git a/doc/filters.texi b/doc/filters.texi
index f20b72ab96..cf884568b0 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -21562,8 +21562,34 @@ The position (byte offset) of the frame in the input stream, or NaN if
this information is unavailable and/or meaningless (for example in case of synthetic video).
Only available with @code{eval=frame}.
Deprecated, do not use.
+
+ at item ref_w, rw
+ at item ref_h, rh
+ at item ref_a
+ at item ref_dar, rdar
+ at item ref_n
+ at item ref_t
+ at item ref_pos
+Eqvuialent to the above, but for a second reference input. If any of these
+variables are present, this filter accepts two inputs.
@end table
+ at subsection Examples
+
+ at itemize
+ at item
+Scale a subtitle stream (sub) to match the main video (main) in size before overlaying
+ at example
+'[main]split[a][b]; [ref][a]scale=rw:rh[c]; [b][c]overlay'
+ at end example
+
+ at item
+Scale a logo to 1/10th the height of a video, while preserving its display aspect ratio.
+ at example
+[logo-in][video-in]scale=w=oh*dar:h=rh/10[logo-out]
+ at end example
+ at end itemize
+
@section scale2ref
Scale (resize) the input video, based on a reference video.
diff --git a/libavfilter/vf_scale.c b/libavfilter/vf_scale.c
index a986dc97ae..f174651333 100644
--- a/libavfilter/vf_scale.c
+++ b/libavfilter/vf_scale.c
@@ -59,6 +59,17 @@ static const char *const var_names[] = {
#if FF_API_FRAME_PKT
"pos",
#endif
+ "ref_w", "rw",
+ "ref_h", "rh",
+ "ref_a",
+ "ref_sar",
+ "ref_dar", "rdar",
+ "ref_hsub",
+ "ref_vsub",
+ "ref_n",
+ "ref_t",
+ "ref_pos",
+ /* Legacy variables for scale2ref */
"main_w",
"main_h",
"main_a",
@@ -89,6 +100,16 @@ enum var_name {
#if FF_API_FRAME_PKT
VAR_POS,
#endif
+ VAR_REF_W, VAR_RW,
+ VAR_REF_H, VAR_RH,
+ VAR_REF_A,
+ VAR_REF_SAR,
+ VAR_REF_DAR, VAR_RDAR,
+ VAR_REF_HSUB,
+ VAR_REF_VSUB,
+ VAR_REF_N,
+ VAR_REF_T,
+ VAR_REF_POS,
VAR_S2R_MAIN_W,
VAR_S2R_MAIN_H,
VAR_S2R_MAIN_A,
@@ -131,6 +152,7 @@ typedef struct ScaleContext {
int input_is_pal; ///< set to 1 if the input format is paletted
int output_is_pal; ///< set to 1 if the output format is paletted
int interlaced;
+ int uses_ref;
char *w_expr; ///< width expression string
char *h_expr; ///< height expression string
@@ -190,6 +212,38 @@ static int check_exprs(AVFilterContext *ctx)
av_log(ctx, AV_LOG_WARNING, "Circular references detected for width '%s' and height '%s' - possibly invalid.\n", scale->w_expr, scale->h_expr);
}
+ if (vars_w[VAR_REF_W] || vars_h[VAR_REF_W] ||
+ vars_w[VAR_RW] || vars_h[VAR_RW] ||
+ vars_w[VAR_REF_H] || vars_h[VAR_REF_H] ||
+ vars_w[VAR_RH] || vars_h[VAR_RH] ||
+ vars_w[VAR_REF_A] || vars_h[VAR_REF_A] ||
+ vars_w[VAR_REF_SAR] || vars_h[VAR_REF_SAR] ||
+ vars_w[VAR_REF_DAR] || vars_h[VAR_REF_DAR] ||
+ vars_w[VAR_RDAR] || vars_h[VAR_RDAR] ||
+ vars_w[VAR_REF_HSUB] || vars_h[VAR_REF_HSUB] ||
+ vars_w[VAR_REF_VSUB] || vars_h[VAR_REF_VSUB] ||
+ vars_w[VAR_REF_N] || vars_h[VAR_REF_N] ||
+ vars_w[VAR_REF_T] || vars_h[VAR_REF_T] ||
+ vars_w[VAR_REF_POS] || vars_h[VAR_REF_POS]) {
+ scale->uses_ref = 1;
+ }
+
+ if (ctx->filter != &ff_vf_scale2ref &&
+ (vars_w[VAR_S2R_MAIN_W] || vars_h[VAR_S2R_MAIN_W] ||
+ vars_w[VAR_S2R_MAIN_H] || vars_h[VAR_S2R_MAIN_H] ||
+ vars_w[VAR_S2R_MAIN_A] || vars_h[VAR_S2R_MAIN_A] ||
+ vars_w[VAR_S2R_MAIN_SAR] || vars_h[VAR_S2R_MAIN_SAR] ||
+ vars_w[VAR_S2R_MAIN_DAR] || vars_h[VAR_S2R_MAIN_DAR] ||
+ vars_w[VAR_S2R_MDAR] || vars_h[VAR_S2R_MDAR] ||
+ vars_w[VAR_S2R_MAIN_HSUB] || vars_h[VAR_S2R_MAIN_HSUB] ||
+ vars_w[VAR_S2R_MAIN_VSUB] || vars_h[VAR_S2R_MAIN_VSUB] ||
+ vars_w[VAR_S2R_MAIN_N] || vars_h[VAR_S2R_MAIN_N] ||
+ vars_w[VAR_S2R_MAIN_T] || vars_h[VAR_S2R_MAIN_T] ||
+ vars_w[VAR_S2R_MAIN_POS] || vars_h[VAR_S2R_MAIN_POS]) ) {
+ av_log(ctx, AV_LOG_ERROR, "Expressions with scale2ref variables are not valid in scale filter.\n");
+ return AVERROR(EINVAL);
+ }
+
if (ctx->filter != &ff_vf_scale2ref &&
(vars_w[VAR_S2R_MAIN_W] || vars_h[VAR_S2R_MAIN_W] ||
vars_w[VAR_S2R_MAIN_H] || vars_h[VAR_S2R_MAIN_H] ||
@@ -385,6 +439,9 @@ static av_cold int init(AVFilterContext *ctx)
if (!threads)
av_opt_set_int(scale->sws_opts, "threads", ff_filter_get_nb_threads(ctx), 0);
+ if (ctx->filter != &ff_vf_scale2ref)
+ ctx->nb_inputs = scale->uses_ref ? 2 : 1;
+
return 0;
}
@@ -506,6 +563,20 @@ static int scale_eval_dimensions(AVFilterContext *ctx)
scale->var_values[VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;
}
+ if (scale->uses_ref) {
+ const AVFilterLink *reflink = ctx->inputs[1];
+ const AVPixFmtDescriptor *ref_desc = av_pix_fmt_desc_get(reflink->format);
+ scale->var_values[VAR_REF_W] = scale->var_values[VAR_RW] = reflink->w;
+ scale->var_values[VAR_REF_H] = scale->var_values[VAR_RH] = reflink->h;
+ scale->var_values[VAR_REF_A] = (double) reflink->w / reflink->h;
+ scale->var_values[VAR_REF_SAR] = reflink->sample_aspect_ratio.num ?
+ (double) reflink->sample_aspect_ratio.num / reflink->sample_aspect_ratio.den : 1;
+ scale->var_values[VAR_REF_DAR] = scale->var_values[VAR_RDAR] =
+ scale->var_values[VAR_REF_A] * scale->var_values[VAR_REF_SAR];
+ scale->var_values[VAR_REF_HSUB] = 1 << ref_desc->log2_chroma_w;
+ scale->var_values[VAR_REF_VSUB] = 1 << ref_desc->log2_chroma_h;
+ }
+
res = av_expr_eval(scale->w_pexpr, scale->var_values, NULL);
eval_w = scale->var_values[VAR_OUT_W] = scale->var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
@@ -693,6 +764,13 @@ static int config_props(AVFilterLink *outlink)
scale->fs.in[0].sync = 1;
scale->fs.in[0].before = EXT_STOP;
scale->fs.in[0].after = EXT_STOP;
+ if (scale->uses_ref) {
+ av_assert0(ctx->nb_inputs == 2);
+ scale->fs.in[1].time_base = ctx->inputs[1]->time_base;
+ scale->fs.in[1].sync = 0;
+ scale->fs.in[1].before = EXT_NULL;
+ scale->fs.in[1].after = EXT_INFINITY;
+ }
ret = ff_framesync_configure(&scale->fs);
if (ret < 0)
@@ -919,13 +997,55 @@ scale:
static int do_scale(FFFrameSync *fs)
{
AVFilterContext *ctx = fs->parent;
+ ScaleContext *scale = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
- AVFrame *in, *out;
- int ret;
+ AVFrame *out, *in = NULL, *ref = NULL;
+ int ret = 0, frame_changed;
ret = ff_framesync_get_frame(fs, 0, &in, 1);
if (ret < 0)
- return ret;
+ goto err;
+
+ if (scale->uses_ref) {
+ ret = ff_framesync_get_frame(fs, 1, &ref, 0);
+ if (ret < 0)
+ goto err;
+ }
+
+ if (ref) {
+ AVFilterLink *reflink = ctx->inputs[1];
+ frame_changed = ref->width != reflink->w ||
+ ref->height != reflink->h ||
+ ref->format != reflink->format ||
+ ref->sample_aspect_ratio.den != reflink->sample_aspect_ratio.den ||
+ ref->sample_aspect_ratio.num != reflink->sample_aspect_ratio.num ||
+ ref->colorspace != reflink->colorspace ||
+ ref->color_range != reflink->color_range;
+
+ if (frame_changed) {
+ reflink->format = ref->format;
+ reflink->w = ref->width;
+ reflink->h = ref->height;
+ reflink->sample_aspect_ratio.num = ref->sample_aspect_ratio.num;
+ reflink->sample_aspect_ratio.den = ref->sample_aspect_ratio.den;
+ reflink->colorspace = ref->colorspace;
+ reflink->color_range = ref->color_range;
+
+ ret = config_props(outlink);
+ if (ret < 0)
+ goto err;
+ }
+
+ if (scale->eval_mode == EVAL_MODE_FRAME) {
+ scale->var_values[VAR_REF_N] = reflink->frame_count_out;
+ scale->var_values[VAR_REF_T] = TS2T(ref->pts, reflink->time_base);
+#if FF_API_FRAME_PKT
+FF_DISABLE_DEPRECATION_WARNINGS
+ scale->var_values[VAR_REF_POS] = ref->pkt_pos == -1 ? NAN : ref->pkt_pos;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+ }
+ }
ret = scale_frame(ctx->inputs[0], in, &out);
if (out) {
@@ -933,6 +1053,9 @@ static int do_scale(FFFrameSync *fs)
return ff_filter_frame(outlink, out);
}
+err:
+ if (ret < 0)
+ av_frame_free(&in);
return ret;
}
@@ -1108,6 +1231,9 @@ static const AVFilterPad avfilter_vf_scale_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
+ }, {
+ .name = "ref",
+ .type = AVMEDIA_TYPE_VIDEO,
},
};
--
2.44.0
More information about the ffmpeg-devel
mailing list