[FFmpeg-devel] [WIP][PATCH] avfilter: add video oscilloscope filter

Dave Rice dave at dericed.com
Wed Apr 26 07:12:49 EEST 2017


> On Apr 25, 2017, at 6:15 PM, Paul B Mahol <onemda at gmail.com> wrote:
> 
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> libavfilter/Makefile       |   1 +
> libavfilter/allfilters.c   |   1 +
> libavfilter/vf_datascope.c | 299 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 301 insertions(+)
> 
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index e40c6fe..66c36e4 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -236,6 +236,7 @@ OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
> OBJS-$(CONFIG_OCR_FILTER)                    += vf_ocr.o
> OBJS-$(CONFIG_OCV_FILTER)                    += vf_libopencv.o
> OBJS-$(CONFIG_OPENCL)                        += deshake_opencl.o unsharp_opencl.o
> +OBJS-$(CONFIG_OSCILLOSCOPE_FILTER)           += vf_datascope.o
> OBJS-$(CONFIG_OVERLAY_FILTER)                += vf_overlay.o dualinput.o framesync.o
> OBJS-$(CONFIG_OWDENOISE_FILTER)              += vf_owdenoise.o
> OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 0852b54..8fb87eb 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -246,6 +246,7 @@ static void register_all(void)
>     REGISTER_FILTER(NULL,           null,           vf);
>     REGISTER_FILTER(OCR,            ocr,            vf);
>     REGISTER_FILTER(OCV,            ocv,            vf);
> +    REGISTER_FILTER(OSCILLOSCOPE,   oscilloscope,   vf);
>     REGISTER_FILTER(OVERLAY,        overlay,        vf);
>     REGISTER_FILTER(OWDENOISE,      owdenoise,      vf);
>     REGISTER_FILTER(PAD,            pad,            vf);
> diff --git a/libavfilter/vf_datascope.c b/libavfilter/vf_datascope.c
> index 5ad4bb8..080a97d 100644
> --- a/libavfilter/vf_datascope.c
> +++ b/libavfilter/vf_datascope.c
> @@ -630,3 +630,302 @@ AVFilter ff_vf_pixscope = {
>     .inputs        = pixscope_inputs,
>     .outputs       = pixscope_outputs,
> };
> +
> +typedef struct PixelValues {
> +    uint16_t p[4];
> +} PixelValues;
> +
> +typedef struct OscilloscopeContext {
> +    const AVClass *class;
> +
> +    float xpos, ypos;
> +    float ty;
> +    float size;
> +    float tilt;
> +    float tsize;
> +    float o;
> +    int components;
> +    int grid;
> +
> +    int x1, y1, x2, y2;
> +    int ox, oy;
> +    int width;
> +
> +    int nb_planes;
> +    int nb_comps;
> +    int is_rgb;
> +    uint8_t rgba_map[4];
> +    FFDrawContext draw;
> +    FFDrawColor   dark;
> +    FFDrawColor   black;
> +    FFDrawColor   white;
> +    FFDrawColor   green;
> +    FFDrawColor   blue;
> +    FFDrawColor   red;
> +    FFDrawColor   gray;
> +    FFDrawColor  *colors[4];
> +
> +    int nb_values;
> +    PixelValues  *values;
> +
> +    void (*pick_color)(FFDrawContext *draw, FFDrawColor *color, AVFrame *in, int x, int y, int *value);
> +} OscilloscopeContext;
> +
> +#define OOFFSET(x) offsetof(OscilloscopeContext, x)
> +
> +static const AVOption oscilloscope_options[] = {
> +    { "x",    "set scope x position", OOFFSET(xpos),    AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },
> +    { "y",    "set scope y position", OOFFSET(ypos),    AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },

I’m curious why floats are used for x,y coordinates within a frame rather than integers.

> +    { "s",    "set scope size",       OOFFSET(size),    AV_OPT_TYPE_FLOAT, {.dbl=0.8}, 0, 1, FLAGS },
> +    { "t",    "set scope tilt",       OOFFSET(tilt),    AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },
> +    { "o",    "set opacity",          OOFFSET(o),       AV_OPT_TYPE_FLOAT, {.dbl=0.8}, 0, 1, FLAGS },
> +    { "ty",   "set trace y position", OOFFSET(ty),      AV_OPT_TYPE_FLOAT, {.dbl=0.9}, 0, 1, FLAGS },
> +    { "ts",   "set trace size",       OOFFSET(tsize),   AV_OPT_TYPE_FLOAT, {.dbl=0.8},.1, 1, FLAGS },
> +    { "c",    "set components to trace", OOFFSET(components), AV_OPT_TYPE_INT,  {.i64=7}, 0, 15, FLAGS },
> +    { "g",    "draw trace grid",      OOFFSET(grid),    AV_OPT_TYPE_BOOL,  {.i64=0},   0, 1, FLAGS },
> +    { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(oscilloscope);
> +
> +static void oscilloscope_uninit(AVFilterContext *ctx)
> +{
> +    OscilloscopeContext *s = ctx->priv;
> +
> +    av_freep(&s->values);
> +}
> +
> +static int oscilloscope_config_input(AVFilterLink *inlink)
> +{
> +    OscilloscopeContext *s = inlink->dst->priv;
> +    int cx, cy, size;
> +    float tilt;
> +
> +    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
> +    ff_draw_init(&s->draw, inlink->format, 0);
> +    ff_draw_color(&s->draw, &s->dark,  (uint8_t[]){ 0, 0, 0, s->o * 255} );
> +    ff_draw_color(&s->draw, &s->black, (uint8_t[]){ 0, 0, 0, 255} );
> +    ff_draw_color(&s->draw, &s->white, (uint8_t[]){ 255, 255, 255, 255} );
> +    ff_draw_color(&s->draw, &s->green, (uint8_t[]){   0, 255,   0, 255} );
> +    ff_draw_color(&s->draw, &s->blue,  (uint8_t[]){   0,   0, 255, 255} );
> +    ff_draw_color(&s->draw, &s->red,   (uint8_t[]){ 255,   0,   0, 255} );
> +    ff_draw_color(&s->draw, &s->gray,  (uint8_t[]){ 128, 128, 128, 255} );
> +    s->nb_comps = s->draw.desc->nb_components;
> +    s->is_rgb   = s->draw.desc->flags & AV_PIX_FMT_FLAG_RGB;
> +
> +    if (s->is_rgb) {
> +        s->colors[0] = &s->red;
> +        s->colors[1] = &s->green;
> +        s->colors[2] = &s->blue;
> +        s->colors[3] = &s->white;
> +        ff_fill_rgba_map(s->rgba_map, inlink->format);
> +    } else {
> +        s->colors[0] = &s->white;
> +        s->colors[1] = &s->blue;
> +        s->colors[2] = &s->red;
> +        s->colors[3] = &s->white;
> +        s->rgba_map[0] = 0;
> +        s->rgba_map[1] = 1;
> +        s->rgba_map[2] = 2;
> +        s->rgba_map[3] = 3;
> +    }
> +
> +    if (s->draw.desc->comp[0].depth <= 8) {
> +        s->pick_color = pick_color8;
> +    } else {
> +        s->pick_color = pick_color16;
> +    }
> +
> +    if (inlink->h < 300) {
> +        av_log(inlink->dst, AV_LOG_ERROR, "min supported height is 300\n");
> +        return AVERROR(EINVAL);
> +    }
> +
> +    cx = s->xpos * inlink->w;
> +    cy = s->ypos * inlink->h;
> +    size = s->size * hypot(inlink->w, inlink->h);
> +    s->width = s->tsize * (inlink->w);
> +
> +    s->values = av_calloc(size, sizeof(*s->values));
> +    if (!s->values)
> +        return AVERROR(ENOMEM);
> +
> +    tilt  = (s->tilt - 0.5) * M_PI;
> +    s->x1 = cx - size / 2.0 * cosf(tilt);
> +    s->x2 = cx + size / 2.0 * cosf(tilt);
> +    s->y1 = cy - size / 2.0 * sinf(tilt);
> +    s->y2 = cy + size / 2.0 * sinf(tilt);
> +    s->ox = (inlink->w - s->width) >> 1;
> +    s->oy = (inlink->h - 300) * s->ty;
> +
> +    return 0;
> +}
> +
> +static void draw_scope(OscilloscopeContext *s, int x0, int y0, int x1, int y1,
> +                       AVFrame *out, PixelValues *p)
> +{
> +    int dx = FFABS(x1 - x0), sx = x0 < x1 ? 1 : -1;
> +    int dy = FFABS(y1 - y0), sy = y0 < y1 ? 1 : -1;
> +    int err = (dx > dy ? dx : -dy) / 2, e2;
> +
> +    for (;;) {
> +        if (x0 > 0 && y0 > 0 && x0 < out->width && y0 < out->height) {
> +            FFDrawColor color = { { 0 } };
> +            int value[4] = { 0 };
> +
> +            s->pick_color(&s->draw, &color, out, x0, y0, value);
> +            s->values[s->nb_values].p[0] = value[0];
> +            s->values[s->nb_values].p[1] = value[1];
> +            s->values[s->nb_values].p[2] = value[2];
> +            s->values[s->nb_values].p[3] = value[3];
> +            s->nb_values++;
> +
> +            if (s->draw.nb_planes == 1) {
> +                int i;
> +
> +                for (i = 0; i < s->draw.pixelstep[0]; i++)
> +                    out->data[0][out->linesize[0] * y0 + x0 * s->draw.pixelstep[0] + i] = 255;
> +            } else {
> +                out->data[0][out->linesize[0] * y0 + x0] = 255;
> +            }
> +        }
> +
> +        if (x0 == x1 && y0 == y1)
> +            break;
> +
> +        e2 = err;
> +
> +        if (e2 >-dx) {
> +            err -= dy;
> +            x0 += sx;
> +        }
> +
> +        if (e2 < dy) {
> +            err += dx;
> +            y0 += sy;
> +        }
> +    }
> +}
> +
> +static void draw_line(FFDrawContext *draw, int x0, int y0, int x1, int y1,
> +                      AVFrame *out, FFDrawColor *color)
> +{
> +    int dx = FFABS(x1 - x0), sx = x0 < x1 ? 1 : -1;
> +    int dy = FFABS(y1 - y0), sy = y0 < y1 ? 1 : -1;
> +    int err = (dx > dy ? dx : -dy) / 2, e2;
> +    int p, i;
> +
> +    for (;;) {
> +        for (p = 0; p < draw->nb_planes; p++) {
> +            if (draw->nb_planes == 1) {
> +                for (i = 0; i < 4; i++) {
> +                    out->data[0][y0 * out->linesize[0] + x0 * draw->pixelstep[0] + i] = color->comp[0].u8[i];
> +                }
> +            } else {
> +                out->data[p][out->linesize[p] * (y0 >> draw->vsub[p]) + (x0 >> draw->hsub[p])] = color->comp[p].u8[0];
> +            }
> +        }
> +
> +        if (x0 == x1 && y0 == y1)
> +            break;
> +
> +        e2 = err;
> +
> +        if (e2 >-dx) {
> +            err -= dy;
> +            x0 += sx;
> +        }
> +
> +        if (e2 < dy) {
> +            err += dx;
> +            y0 += sy;
> +        }
> +    }
> +}
> +
> +static int oscilloscope_filter_frame(AVFilterLink *inlink, AVFrame *frame)
> +{
> +    AVFilterContext *ctx  = inlink->dst;
> +    OscilloscopeContext *s = ctx->priv;
> +    AVFilterLink *outlink = ctx->outputs[0];
> +    float average[4] = { 0 };
> +    int max[4] = { 0 };
> +    int min[4] = { INT_MAX, INT_MAX, INT_MAX, INT_MAX };
> +    int i, c;
> +
> +    s->nb_values = 0;
> +    draw_scope(s, s->x1, s->y1, s->x2, s->y2, frame, s->values);
> +    ff_blend_rectangle(&s->draw, &s->dark, frame->data, frame->linesize,
> +                       frame->width, frame->height,
> +                       s->ox, s->oy, s->width, 300);

It appears that the plotted scope is padded to 300, though the trace usually is 256 (2^8) lines tall. Are the other 44 lines intended to store something?

> +    if (s->grid) {
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox, s->oy, s->width - 1, 1);
> +
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox, s->oy + 64, s->width, 1);
> +
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox, s->oy + 128, s->width, 1);
> +
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox, s->oy + 192, s->width, 1);
> +
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox, s->oy + 256, s->width, 1);
> +
> +        for (i = 0; i < 10; i++) {
> +            ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                              s->ox + i * (s->width - 1) / 10, s->oy, 1, 256);
> +        }
> +
> +        ff_fill_rectangle(&s->draw, &s->gray, frame->data, frame->linesize,
> +                          s->ox + s->width - 1, s->oy, 1, 256);
> +    }
> +
> +    for (i = 1; i < s->nb_values; i++) {
> +        for (c = 0; c < s->nb_comps; c++) {
> +            if ((1 << c) & s->components) {
> +                int x = i * s->width / s->nb_values;
> +                int px = (i - 1) * s->width / s->nb_values;
> +                int py = 255 - s->values[i-1].p[c];
> +                int y = 255 - s->values[i].p[c];
> +
> +                draw_line(&s->draw, s->ox + x, s->oy + y, s->ox + px, s->oy + py, frame, s->colors[c]);
> +            }
> +        }
> +    }
> +
> +    return ff_filter_frame(outlink, frame);
> +}
> +
> +static const AVFilterPad oscilloscope_inputs[] = {
> +    {
> +        .name           = "default",
> +        .type           = AVMEDIA_TYPE_VIDEO,
> +        .filter_frame   = oscilloscope_filter_frame,
> +        .config_props   = oscilloscope_config_input,
> +        .needs_writable = 1,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad oscilloscope_outputs[] = {
> +    {
> +        .name         = "default",
> +        .type         = AVMEDIA_TYPE_VIDEO,
> +    },
> +    { NULL }
> +};
> +
> +AVFilter ff_vf_oscilloscope = {
> +    .name          = "oscilloscope",
> +    .description   = NULL_IF_CONFIG_SMALL("2D Video Oscilloscope."),
> +    .priv_size     = sizeof(OscilloscopeContext),
> +    .priv_class    = &oscilloscope_class,
> +    .query_formats = query_formats,
> +    .uninit        = oscilloscope_uninit,
> +    .inputs        = oscilloscope_inputs,
> +    .outputs       = oscilloscope_outputs,
> +};
> -- 
> 2.9.3

A crash on >8 bit:

./ffplay -f lavfi -i mandelbrot -vf format=yuv422p10le,oscilloscope
ffplay version N-85657-gd2e300a0a0 Copyright (c) 2003-2017 the FFmpeg developers
  built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  configuration: --disable-dwt
  libavutil      55. 61.100 / 55. 61.100
  libavcodec     57. 93.100 / 57. 93.100
  libavformat    57. 72.101 / 57. 72.101
  libavdevice    57.  7.100 / 57.  7.100
  libavfilter     6. 87.100 /  6. 87.100
  libswscale      4.  7.101 /  4.  7.101
  libswresample   2.  8.100 /  2.  8.100
Input #0, lavfi, from 'mandelbrot':0KB vq=    0KB sq=    0B f=0/0   
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (RGB[0] / 0x424752), rgb0, 640x480 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
Segmentation fault: 11


Dave Rice


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