[FFmpeg-devel] [PATCH v2 0/2] avfilter/vf_thumbnail: support more formats

[FFmpeg-devel] [PATCH v2 0/2] avfilter/vf_thumbnail: support more formats

[Niklas Haas]

Changes since v1:
- merge the 16-bit and 8-bit cases to reduce a bit of code duplication
- add the support for grayscale formats as well
- switch to query_func2 instead of hard-coding the format list

I'm not sure I like the complicated logic inside query_func2 now, it feels
like it hard-codes just as many assumptions as a static list.

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[FFmpeg-devel] [PATCH v2 1/2] avfilter/vf_thumbnail: support more planar formats

[Niklas Haas]

From: Niklas Haas <git@haasn.dev>

This adds support for high bit depth formats, as well as formats with fewer
than 3 planes. The implementation for HBD is the same as for 8 bit formats,
just right shifted to 8 bits.

It's worth pointing out that this also works for HDR formats (and even DV),
because the underlying implementation is just trying to minimize the histogram
difference. If anything, using a HDR format will result in a *more* accurate
detection, because HDR formats tend to be more perceptually uniform.
---
 libavfilter/vf_thumbnail.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/libavfilter/vf_thumbnail.c b/libavfilter/vf_thumbnail.c
index 90125a879c..55a0598e50 100644
--- a/libavfilter/vf_thumbnail.c
+++ b/libavfilter/vf_thumbnail.c
@@ -53,6 +53,8 @@ typedef struct ThumbContext {
 
     int planewidth[4];
     int planeheight[4];
+    int planes;
+    int bitdepth;
 } ThumbContext;
 
 #define OFFSET(x) offsetof(ThumbContext, x)
@@ -194,7 +196,7 @@ static int do_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
         }
         break;
     default:
-        for (int plane = 0; plane < 3; plane++) {
+        for (int plane = 0; plane < s->planes; plane++) {
             const int slice_start = (s->planeheight[plane] * jobnr) / nb_jobs;
             const int slice_end = (s->planeheight[plane] * (jobnr+1)) / nb_jobs;
             const uint8_t *p = frame->data[plane] + slice_start * frame->linesize[plane];
@@ -202,10 +204,21 @@ static int do_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
             const int planewidth = s->planewidth[plane];
             int *hhist = hist + 256 * plane;
 
-            for (int j = slice_start; j < slice_end; j++) {
-                for (int i = 0; i < planewidth; i++)
-                    hhist[p[i]]++;
-                p += linesize;
+            if (s->bitdepth > 8) {
+                const uint16_t *p16 = (const uint16_t *) p;
+                const int shift = s->bitdepth - 8;
+
+                for (int j = slice_start; j < slice_end; j++) {
+                    for (int i = 0; i < planewidth; i++)
+                        hhist[(p16[i] >> shift) & 0xFF]++;
+                    p16 += linesize >> 1;
+                }
+            } else {
+                for (int j = slice_start; j < slice_end; j++) {
+                    for (int i = 0; i < planewidth; i++)
+                        hhist[p[i]]++;
+                    p += linesize;
+                }
             }
         }
         break;
@@ -286,6 +299,8 @@ static int config_props(AVFilterLink *inlink)
     s->planewidth[0]  = s->planewidth[3]  = inlink->w;
     s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
     s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planes         = av_pix_fmt_count_planes(inlink->format) - !!(desc->flags & AV_PIX_FMT_FLAG_ALPHA);
+    s->bitdepth       = desc->comp[0].depth;
 
     return 0;
 }
-- 
2.49.0

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[FFmpeg-devel] [PATCH v2 2/2] avfilter/vf_thumbnail: switch to query_func2

[Niklas Haas]

From: Niklas Haas <git@haasn.dev>

Instead of enumerating a static list of planar formats to support, walk
through the format list and enable all supported formats.

As of writing, this generates the following format list:
- gbrap
- gbrap10le
- gbrap12le
- gbrap14le
- gbrap16le
- gbrp
- gbrp10le
- gbrp12le
- gbrp14le
- gbrp16le
- gbrp9le
- gray
- gray10le
- gray12le
- gray14le
- gray16le
- gray9le
- ya16le
- ya8
- yuv410p
- yuv411p
- yuv420p
- yuv420p10le
- yuv420p12le
- yuv420p14le
- yuv420p16le
- yuv420p9le
- yuv422p
- yuv422p10le
- yuv422p12le
- yuv422p14le
- yuv422p16le
- yuv422p9le
- yuv440p
- yuv440p10le
- yuv440p12le
- yuv444p
- yuv444p10le
- yuv444p12le
- yuv444p14le
- yuv444p16le
- yuv444p9le
- yuva420p
- yuva420p10le
- yuva420p16le
- yuva420p9le
- yuva422p
- yuva422p10le
- yuva422p12le
- yuva422p16le
- yuva422p9le
- yuva444p
- yuva444p10le
- yuva444p12le
- yuva444p16le
- yuva444p9le
- yuvj411p
- yuvj420p
- yuvj422p
- yuvj440p
- yuvj444p
---
 libavfilter/vf_thumbnail.c | 43 +++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/libavfilter/vf_thumbnail.c b/libavfilter/vf_thumbnail.c
index 55a0598e50..6f7a0ba766 100644
--- a/libavfilter/vf_thumbnail.c
+++ b/libavfilter/vf_thumbnail.c
@@ -32,6 +32,7 @@
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "filters.h"
+#include "formats.h"
 
 #define HIST_SIZE (3*256)
 
@@ -305,23 +306,45 @@ static int config_props(AVFilterLink *inlink)
     return 0;
 }
 
-static const enum AVPixelFormat pix_fmts[] = {
+static const enum AVPixelFormat packed_rgb_fmts[] = {
     AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
     AV_PIX_FMT_RGBA,  AV_PIX_FMT_BGRA,
     AV_PIX_FMT_RGB0,  AV_PIX_FMT_BGR0,
     AV_PIX_FMT_ABGR,  AV_PIX_FMT_ARGB,
     AV_PIX_FMT_0BGR,  AV_PIX_FMT_0RGB,
-    AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
-    AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
-    AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
-    AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
-    AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
-    AV_PIX_FMT_YUVJ411P,
-    AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
-    AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
     AV_PIX_FMT_NONE
 };
 
+static int query_formats(const AVFilterContext *ctx,
+                         AVFilterFormatsConfig **cfg_in,
+                         AVFilterFormatsConfig **cfg_out)
+{
+    const AVPixFmtDescriptor *desc = NULL;
+    AVFilterFormats *formats;
+
+    formats = ff_make_format_list(packed_rgb_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+
+
+    while ((desc = av_pix_fmt_desc_next(desc))) {
+        int color_comps = desc->nb_components - !!(desc->flags & AV_PIX_FMT_FLAG_ALPHA);
+        if ((color_comps == 1 || (desc->flags & AV_PIX_FMT_FLAG_PLANAR)) &&
+            !(desc->flags & (AV_PIX_FMT_FLAG_FLOAT | AV_PIX_FMT_FLAG_BITSTREAM)) &&
+            (desc->comp[0].depth <= 8 || HAVE_BIGENDIAN == !!(desc->flags & AV_PIX_FMT_FLAG_BE)) &&
+            (desc->nb_components < 3 || desc->comp[1].plane != desc->comp[2].plane) &&
+            desc->comp[0].depth <= 16)
+        {
+            printf("Adding format %s\n", desc->name);
+            int ret = ff_add_format(&formats, av_pix_fmt_desc_get_id(desc));
+            if (ret < 0)
+                return ret;
+        }
+    }
+
+    return ff_set_common_formats2(ctx, cfg_in, cfg_out, formats);
+}
+
 static const AVFilterPad thumbnail_inputs[] = {
     {
         .name         = "default",
@@ -350,5 +373,5 @@ const FFFilter ff_vf_thumbnail = {
     .uninit        = uninit,
     FILTER_INPUTS(thumbnail_inputs),
     FILTER_OUTPUTS(thumbnail_outputs),
-    FILTER_PIXFMTS_ARRAY(pix_fmts),
+    FILTER_QUERY_FUNC2(query_formats),
 };
-- 
2.49.0

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Re: [FFmpeg-devel] [PATCH v2 2/2] avfilter/vf_thumbnail: switch to query_func2

[Niklas Haas]

On Fri, 20 Jun 2025 16:13:34 +0200 Niklas Haas <ffmpeg@haasn.xyz> wrote:
> From: Niklas Haas <git@haasn.dev>
>
> Instead of enumerating a static list of planar formats to support, walk
> through the format list and enable all supported formats.
>
> As of writing, this generates the following format list:
> - gbrap
> - gbrap10le
> - gbrap12le
> - gbrap14le
> - gbrap16le
> - gbrp
> - gbrp10le
> - gbrp12le
> - gbrp14le
> - gbrp16le
> - gbrp9le
> - gray
> - gray10le
> - gray12le
> - gray14le
> - gray16le
> - gray9le
> - ya16le
> - ya8
> - yuv410p
> - yuv411p
> - yuv420p
> - yuv420p10le
> - yuv420p12le
> - yuv420p14le
> - yuv420p16le
> - yuv420p9le
> - yuv422p
> - yuv422p10le
> - yuv422p12le
> - yuv422p14le
> - yuv422p16le
> - yuv422p9le
> - yuv440p
> - yuv440p10le
> - yuv440p12le
> - yuv444p
> - yuv444p10le
> - yuv444p12le
> - yuv444p14le
> - yuv444p16le
> - yuv444p9le
> - yuva420p
> - yuva420p10le
> - yuva420p16le
> - yuva420p9le
> - yuva422p
> - yuva422p10le
> - yuva422p12le
> - yuva422p16le
> - yuva422p9le
> - yuva444p
> - yuva444p10le
> - yuva444p12le
> - yuva444p16le
> - yuva444p9le
> - yuvj411p
> - yuvj420p
> - yuvj422p
> - yuvj440p
> - yuvj444p
> ---
>  libavfilter/vf_thumbnail.c | 43 +++++++++++++++++++++++++++++---------
>  1 file changed, 33 insertions(+), 10 deletions(-)
>
> diff --git a/libavfilter/vf_thumbnail.c b/libavfilter/vf_thumbnail.c
> index 55a0598e50..6f7a0ba766 100644
> --- a/libavfilter/vf_thumbnail.c
> +++ b/libavfilter/vf_thumbnail.c
> @@ -32,6 +32,7 @@
>  #include "libavutil/pixdesc.h"
>  #include "avfilter.h"
>  #include "filters.h"
> +#include "formats.h"
>
>  #define HIST_SIZE (3*256)
>
> @@ -305,23 +306,45 @@ static int config_props(AVFilterLink *inlink)
>      return 0;
>  }
>
> -static const enum AVPixelFormat pix_fmts[] = {
> +static const enum AVPixelFormat packed_rgb_fmts[] = {
>      AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,
>      AV_PIX_FMT_RGBA,  AV_PIX_FMT_BGRA,
>      AV_PIX_FMT_RGB0,  AV_PIX_FMT_BGR0,
>      AV_PIX_FMT_ABGR,  AV_PIX_FMT_ARGB,
>      AV_PIX_FMT_0BGR,  AV_PIX_FMT_0RGB,
> -    AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
> -    AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
> -    AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
> -    AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
> -    AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
> -    AV_PIX_FMT_YUVJ411P,
> -    AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
> -    AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
>      AV_PIX_FMT_NONE
>  };
>
> +static int query_formats(const AVFilterContext *ctx,
> +                         AVFilterFormatsConfig **cfg_in,
> +                         AVFilterFormatsConfig **cfg_out)
> +{
> +    const AVPixFmtDescriptor *desc = NULL;
> +    AVFilterFormats *formats;
> +
> +    formats = ff_make_format_list(packed_rgb_fmts);
> +    if (!formats)
> +        return AVERROR(ENOMEM);
> +
> +
> +    while ((desc = av_pix_fmt_desc_next(desc))) {
> +        int color_comps = desc->nb_components - !!(desc->flags & AV_PIX_FMT_FLAG_ALPHA);
> +        if ((color_comps == 1 || (desc->flags & AV_PIX_FMT_FLAG_PLANAR)) &&
> +            !(desc->flags & (AV_PIX_FMT_FLAG_FLOAT | AV_PIX_FMT_FLAG_BITSTREAM)) &&
> +            (desc->comp[0].depth <= 8 || HAVE_BIGENDIAN == !!(desc->flags & AV_PIX_FMT_FLAG_BE)) &&
> +            (desc->nb_components < 3 || desc->comp[1].plane != desc->comp[2].plane) &&
> +            desc->comp[0].depth <= 16)
> +        {
> +            printf("Adding format %s\n", desc->name);

Oops, removed this left-over printf locally.

> +            int ret = ff_add_format(&formats, av_pix_fmt_desc_get_id(desc));
> +            if (ret < 0)
> +                return ret;
> +        }
> +    }
> +
> +    return ff_set_common_formats2(ctx, cfg_in, cfg_out, formats);
> +}
> +
>  static const AVFilterPad thumbnail_inputs[] = {
>      {
>          .name         = "default",
> @@ -350,5 +373,5 @@ const FFFilter ff_vf_thumbnail = {
>      .uninit        = uninit,
>      FILTER_INPUTS(thumbnail_inputs),
>      FILTER_OUTPUTS(thumbnail_outputs),
> -    FILTER_PIXFMTS_ARRAY(pix_fmts),
> +    FILTER_QUERY_FUNC2(query_formats),
>  };
> --
> 2.49.0
>
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