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videomixer2: Add transparent background option for alpha channel formats

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This option allows the videomixer2 element to output a valid alpha
channel when the inputs contain a valid alpha channel. This allows
mixing to occur in multiple stages serially.

The following pipeline shows an example of such a pipeline:

gst-launch videotestsrc background-color=0x000000 pattern=ball ! video/x-raw-yuv,format=\(fourcc\)AYUV ! videomixer2 background=transparent name=mix1 ! videomixer2 name=mix2 ! ffmpegcolorspace ! autovideosink  videotestsrc ! video/x-raw-yuv,format=\(fourcc\)AYUV ! mix2.

The first videotestsrc in this pipeline creates a moving ball on a
transparent background. It is then passed to the first videomixer2.
Previously, this videomixer2 would have forced the alpha channel to
1.0 and given a background of checker, black, or white to the
stream. With this patch, however, you can now specify the background
as transparent, and the alpha channel of the input will be
preserved. This allows for further mixing downstream, as is shown in
the above pipeline where the a second videomixer2 is used to mix in a
background of an smpte videotestsrc. So the result is a ball hovering
over the smpte test source. This could, of course, have been
accomplished with a single mixer element, but staged mixing is useful
when it is not convenient to mix all video at once (e.g. a pipeline
where a foreground and background bin exist and are mixed at the final
output, but the foreground bin needs an internal mixer to create
transitions between clips).

Fixes bug #639994.
This commit is contained in:
Lane Brooks 2011-01-19 12:07:17 -07:00 committed by Sebastian Dröge
parent 176b8ffbff
commit 69b5aedc58
5 changed files with 189 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
gst/videomixer/blend.c
View file

@ -41,9 +41,9 @@ GST_DEBUG_CATEGORY_STATIC (gst_videomixer_blend_debug);
/* Below are the implementations of everything */
/* A32 is for AYUV, ARGB and BGRA */
#define BLEND_A32(name, LOOP) \
#define BLEND_A32(name, method, LOOP) \
static void \
blend_##name (const guint8 * src, gint xpos, gint ypos, \
method##_ ##name (const guint8 * src, gint xpos, gint ypos, \
gint src_width, gint src_height, gdouble src_alpha, \
guint8 * dest, gint dest_width, gint dest_height) \
{ \
@ -83,25 +83,31 @@ blend_##name (const guint8 * src, gint xpos, gint ypos, \
LOOP (dest, src, src_height, src_width, src_stride, dest_stride, s_alpha); \
}
#define BLEND_A32_LOOP(name) \
#define BLEND_A32_LOOP(name, method) \
static inline void \
_blend_loop_##name (guint8 * dest, const guint8 * src, gint src_height, \
_##method##_loop_##name (guint8 * dest, const guint8 * src, gint src_height, \
gint src_width, gint src_stride, gint dest_stride, guint s_alpha) \
{ \
s_alpha = MIN (255, s_alpha); \
orc_blend_##name (dest, dest_stride, src, src_stride, \
orc_##method##_##name (dest, dest_stride, src, src_stride, \
s_alpha, src_width, src_height); \
}
BLEND_A32_LOOP (argb);
BLEND_A32_LOOP (bgra);
BLEND_A32_LOOP (argb, blend);
BLEND_A32_LOOP (bgra, blend);
BLEND_A32_LOOP (argb, overlay);
BLEND_A32_LOOP (bgra, overlay);
#if G_BYTE_ORDER == LITTLE_ENDIAN
BLEND_A32 (argb, _blend_loop_argb);
BLEND_A32 (bgra, _blend_loop_bgra);
BLEND_A32 (argb, blend, _blend_loop_argb);
BLEND_A32 (bgra, blend, _blend_loop_bgra);
BLEND_A32 (argb, overlay, _overlay_loop_argb);
BLEND_A32 (bgra, overlay, _overlay_loop_bgra);
#else
BLEND_A32 (argb, _blend_loop_bgra);
BLEND_A32 (bgra, _blend_loop_argb);
BLEND_A32 (argb, blend, _blend_loop_bgra);
BLEND_A32 (bgra, blend, _blend_loop_argb);
BLEND_A32 (argb, overlay, _overlay_loop_bgra);
BLEND_A32 (bgra, overlay, _overlay_loop_argb);
#endif
#define A32_CHECKER_C(name, RGB, A, C1, C2, C3) \
@ -666,6 +672,8 @@ PACKED_422_FILL_COLOR (uyvy, 16, 24, 0, 8);
/* Init function */
BlendFunction gst_video_mixer_blend_argb;
BlendFunction gst_video_mixer_blend_bgra;
BlendFunction gst_video_mixer_overlay_argb;
BlendFunction gst_video_mixer_overlay_bgra;
/* AYUV/ABGR is equal to ARGB, RGBA is equal to BGRA */
BlendFunction gst_video_mixer_blend_y444;
BlendFunction gst_video_mixer_blend_y42b;
@ -724,6 +732,8 @@ gst_video_mixer_init_blend (void)
gst_video_mixer_blend_argb = blend_argb;
gst_video_mixer_blend_bgra = blend_bgra;
gst_video_mixer_overlay_argb = overlay_argb;
gst_video_mixer_overlay_bgra = overlay_bgra;
gst_video_mixer_blend_i420 = blend_i420;
gst_video_mixer_blend_y444 = blend_y444;
gst_video_mixer_blend_y42b = blend_y42b;

5
gst/videomixer/blend.h
View file

@ -31,6 +31,11 @@ extern BlendFunction gst_video_mixer_blend_bgra;
#define gst_video_mixer_blend_ayuv gst_video_mixer_blend_argb
#define gst_video_mixer_blend_abgr gst_video_mixer_blend_argb
#define gst_video_mixer_blend_rgba gst_video_mixer_blend_bgra
extern BlendFunction gst_video_mixer_overlay_argb;
extern BlendFunction gst_video_mixer_overlay_bgra;
#define gst_video_mixer_overlay_ayuv gst_video_mixer_overlay_argb
#define gst_video_mixer_overlay_abgr gst_video_mixer_overlay_argb
#define gst_video_mixer_overlay_rgba gst_video_mixer_overlay_bgra
extern BlendFunction gst_video_mixer_blend_i420;
#define gst_video_mixer_blend_yv12 gst_video_mixer_blend_i420
extern BlendFunction gst_video_mixer_blend_y41b;

125
gst/videomixer/blendorc.orc
View file

@ -95,3 +95,128 @@ x4 convwb t, d_wide
orl t, t, a_alpha
storel d, t
.function orc_overlay_argb
.flags 2d
.dest 4 d guint8
.source 4 s guint8
.param 2 alpha
.temp 4 t
.temp 2 tw
.temp 1 tb
.temp 8 alpha_s
.temp 8 alpha_s_inv
.temp 8 alpha_d
.temp 4 a
.temp 8 d_wide
.temp 8 s_wide
.const 4 xfs 0xffffffff
.const 4 a_alpha 0x000000ff
.const 4 a_alpha_inv 0xffffff00
# calc source alpha as alpha_s = alpha_s * alpha / 256
loadl t, s
convlw tw, t
convwb tb, tw
splatbl a, tb
x4 convubw alpha_s, a
x4 mullw alpha_s, alpha_s, alpha
x4 shruw alpha_s, alpha_s, 8
x4 convubw s_wide, t
x4 mullw s_wide, s_wide, alpha_s
# calc destination alpha as alpha_d = (255-alpha_s) * alpha_d / 255
loadpl a, xfs
x4 convubw alpha_s_inv, a
x4 subw alpha_s_inv, alpha_s_inv, alpha_s
loadl t, d
convlw tw, t
convwb tb, tw
convubw tw, tb
splatbl a, tb
x4 convubw alpha_d, a
x4 mullw alpha_d, alpha_d, alpha_s_inv
x4 div255w alpha_d, alpha_d
x4 convubw d_wide, t
x4 mullw d_wide, d_wide, alpha_d
# calc final pixel as pix_d = pix_s*alpha_s + pix_d*alpha_d*(255-alpha_s)/255
x4 addw d_wide, d_wide, s_wide
# calc the final destination alpha_d = alpha_s + alpha_d * (255-alpha_s)/255
x4 addw alpha_d, alpha_d, alpha_s
# now normalize the pix_d by the final alpha to make it associative
x4 divluw, d_wide, d_wide, alpha_d
# pack the new alpha into the correct spot
x4 convwb t, d_wide
andl t, t, a_alpha_inv
x4 convwb a, alpha_d
andl a, a, a_alpha
orl t, t, a
storel d, t
.function orc_overlay_bgra
.flags 2d
.dest 4 d guint8
.source 4 s guint8
.param 2 alpha
.temp 4 t
.temp 4 t2
.temp 2 tw
.temp 1 tb
.temp 8 alpha_s
.temp 8 alpha_s_inv
.temp 8 alpha_d
.temp 4 a
.temp 8 d_wide
.temp 8 s_wide
.const 4 xfs 0xffffffff
.const 4 a_alpha 0xff000000
.const 4 a_alpha_inv 0x00ffffff
# calc source alpha as alpha_s = alpha_s * alpha / 256
loadl t, s
shrul t2, t, 24
convlw tw, t
convwb tb, tw
splatbl a, tb
x4 convubw alpha_s, a
x4 mullw alpha_s, alpha_s, alpha
x4 shruw alpha_s, alpha_s, 8
x4 convubw s_wide, t
x4 mullw s_wide, s_wide, alpha_s
# calc destination alpha as alpha_d = (255-alpha_s) * alpha_d / 255
loadpl a, xfs
x4 convubw alpha_s_inv, a
x4 subw alpha_s_inv, alpha_s_inv, alpha_s
loadl t, d
shrul t2, t, 24
convlw tw, t
convwb tb, tw
convubw tw, tb
splatbl a, tb
x4 convubw alpha_d, a
x4 mullw alpha_d, alpha_d, alpha_s_inv
x4 div255w alpha_d, alpha_d
x4 convubw d_wide, t
x4 mullw d_wide, d_wide, alpha_d
# calc final pixel as pix_d = pix_s*alpha_s + pix_d*alpha_d*(255-alpha_s)/255
x4 addw d_wide, d_wide, s_wide
# calc the final destination alpha_d = alpha_s + alpha_d * (255-alpha_s)/255
x4 addw alpha_d, alpha_d, alpha_s
# now normalize the pix_d by the final alpha to make it associative
x4 divluw, d_wide, d_wide, alpha_d
# pack the new alpha into the correct spot
x4 convwb t, d_wide
andl t, t, a_alpha_inv
x4 convwb a, alpha_d
andl a, a, a_alpha
orl t, t, a
storel d, t

36
gst/videomixer/videomixer2.c
View file

@ -546,6 +546,8 @@ gst_videomixer2_background_get_type (void)
{VIDEO_MIXER2_BACKGROUND_CHECKER, "Checker pattern", "checker"},
{VIDEO_MIXER2_BACKGROUND_BLACK, "Black", "black"},
{VIDEO_MIXER2_BACKGROUND_WHITE, "White", "white"},
{VIDEO_MIXER2_BACKGROUND_TRANSPARENT,
"Transparent Background to enable further mixing", "transparent"},
{0, NULL, NULL},
};
@ -810,6 +812,7 @@ gst_videomixer2_blend_buffers (GstVideoMixer2 * mix,
GSList *l;
GstFlowReturn ret;
guint outsize;
BlendFunction composite;
outsize = gst_video_format_get_size (mix->format, mix->width, mix->height);
ret = gst_pad_alloc_buffer_and_set_caps (mix->srcpad, GST_BUFFER_OFFSET_NONE,
@ -820,6 +823,8 @@ gst_videomixer2_blend_buffers (GstVideoMixer2 * mix,
GST_BUFFER_TIMESTAMP (*outbuf) = output_start_time;
GST_BUFFER_DURATION (*outbuf) = output_end_time - output_start_time;
/* default to blending */
composite = mix->blend;
switch (mix->background) {
case VIDEO_MIXER2_BACKGROUND_CHECKER:
mix->fill_checker (GST_BUFFER_DATA (*outbuf), mix->width, mix->height);
@ -832,6 +837,13 @@ gst_videomixer2_blend_buffers (GstVideoMixer2 * mix,
mix->fill_color (GST_BUFFER_DATA (*outbuf), mix->width,
mix->height, 240, 128, 128);
break;
case VIDEO_MIXER2_BACKGROUND_TRANSPARENT:
memset (GST_BUFFER_DATA (*outbuf), 0,
gst_video_format_get_row_stride (mix->format, 0,
mix->width) * mix->height);
/* use overlay to keep background transparent */
composite = mix->overlay;
break;
}
for (l = mix->sinkpads; l; l = l->next) {
@ -854,7 +866,7 @@ gst_videomixer2_blend_buffers (GstVideoMixer2 * mix,
if (GST_CLOCK_TIME_IS_VALID (stream_time))
gst_object_sync_values (G_OBJECT (pad), stream_time);
mix->blend (GST_BUFFER_DATA (mixcol->buffer),
composite (GST_BUFFER_DATA (mixcol->buffer),
pad->xpos, pad->ypos, pad->width, pad->height, pad->alpha,
GST_BUFFER_DATA (*outbuf), mix->width, mix->height);
}
@ -1387,6 +1399,7 @@ gst_videomixer2_src_setcaps (GstPad * pad, GstCaps * caps)
GST_INFO_OBJECT (pad, "set src caps: %" GST_PTR_FORMAT, caps);
mix->blend = NULL;
mix->overlay = NULL;
mix->fill_checker = NULL;
mix->fill_color = NULL;
@ -1416,114 +1429,133 @@ gst_videomixer2_src_setcaps (GstPad * pad, GstCaps * caps)
switch (mix->format) {
case GST_VIDEO_FORMAT_AYUV:
mix->blend = gst_video_mixer_blend_ayuv;
mix->overlay = gst_video_mixer_overlay_ayuv;
mix->fill_checker = gst_video_mixer_fill_checker_ayuv;
mix->fill_color = gst_video_mixer_fill_color_ayuv;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_ARGB:
mix->blend = gst_video_mixer_blend_argb;
mix->overlay = gst_video_mixer_overlay_argb;
mix->fill_checker = gst_video_mixer_fill_checker_argb;
mix->fill_color = gst_video_mixer_fill_color_argb;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_BGRA:
mix->blend = gst_video_mixer_blend_bgra;
mix->overlay = gst_video_mixer_overlay_bgra;
mix->fill_checker = gst_video_mixer_fill_checker_bgra;
mix->fill_color = gst_video_mixer_fill_color_bgra;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_ABGR:
mix->blend = gst_video_mixer_blend_abgr;
mix->overlay = gst_video_mixer_overlay_abgr;
mix->fill_checker = gst_video_mixer_fill_checker_abgr;
mix->fill_color = gst_video_mixer_fill_color_abgr;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_RGBA:
mix->blend = gst_video_mixer_blend_rgba;
mix->overlay = gst_video_mixer_overlay_rgba;
mix->fill_checker = gst_video_mixer_fill_checker_rgba;
mix->fill_color = gst_video_mixer_fill_color_rgba;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_Y444:
mix->blend = gst_video_mixer_blend_y444;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_y444;
mix->fill_color = gst_video_mixer_fill_color_y444;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_Y42B:
mix->blend = gst_video_mixer_blend_y42b;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_y42b;
mix->fill_color = gst_video_mixer_fill_color_y42b;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_YUY2:
mix->blend = gst_video_mixer_blend_yuy2;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_yuy2;
mix->fill_color = gst_video_mixer_fill_color_yuy2;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_UYVY:
mix->blend = gst_video_mixer_blend_uyvy;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_uyvy;
mix->fill_color = gst_video_mixer_fill_color_uyvy;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_YVYU:
mix->blend = gst_video_mixer_blend_yvyu;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_yvyu;
mix->fill_color = gst_video_mixer_fill_color_yvyu;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_I420:
mix->blend = gst_video_mixer_blend_i420;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_i420;
mix->fill_color = gst_video_mixer_fill_color_i420;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_YV12:
mix->blend = gst_video_mixer_blend_yv12;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_yv12;
mix->fill_color = gst_video_mixer_fill_color_yv12;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_Y41B:
mix->blend = gst_video_mixer_blend_y41b;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_y41b;
mix->fill_color = gst_video_mixer_fill_color_y41b;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_RGB:
mix->blend = gst_video_mixer_blend_rgb;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_rgb;
mix->fill_color = gst_video_mixer_fill_color_rgb;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_BGR:
mix->blend = gst_video_mixer_blend_bgr;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_bgr;
mix->fill_color = gst_video_mixer_fill_color_bgr;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_xRGB:
mix->blend = gst_video_mixer_blend_xrgb;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_xrgb;
mix->fill_color = gst_video_mixer_fill_color_xrgb;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_xBGR:
mix->blend = gst_video_mixer_blend_xbgr;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_xbgr;
mix->fill_color = gst_video_mixer_fill_color_xbgr;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_RGBx:
mix->blend = gst_video_mixer_blend_rgbx;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_rgbx;
mix->fill_color = gst_video_mixer_fill_color_rgbx;
ret = TRUE;
break;
case GST_VIDEO_FORMAT_BGRx:
mix->blend = gst_video_mixer_blend_bgrx;
mix->overlay = mix->blend;
mix->fill_checker = gst_video_mixer_fill_checker_bgrx;
mix->fill_color = gst_video_mixer_fill_color_bgrx;
ret = TRUE;
@ -1599,7 +1631,7 @@ gst_videomixer2_sink_event (GstCollectPads2 * pads, GstCollectData2 * cdata,
GST_DEBUG_OBJECT (pad, "Got %s event on pad %s:%s",
GST_EVENT_TYPE_NAME (event), GST_DEBUG_PAD_NAME (pad));
// return FALSE => event will be forwarded
/* return FALSE => event will be forwarded */
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_NEWSEGMENT:{
GstFormat fmt;

6
gst/videomixer/videomixer2.h
View file

@ -47,6 +47,7 @@ typedef struct _GstVideoMixer2Class GstVideoMixer2Class;
* @VIDEO_MIXER2_BACKGROUND_CHECKER: checker pattern background
* @VIDEO_MIXER2_BACKGROUND_BLACK: solid color black background
* @VIDEO_MIXER2_BACKGROUND_WHITE: solid color white background
* @VIDEO_MIXER2_BACKGROUND_TRANSPARENT: background is left transparent and layers are composited using "A OVER B" composition rules. This is only applicable to AYUV and ARGB (and variants) as it preserves the alpha channel and allows for further mixing.
*
* The different backgrounds videomixer can blend over.
*/
@ -54,7 +55,8 @@ typedef enum
{
VIDEO_MIXER2_BACKGROUND_CHECKER,
VIDEO_MIXER2_BACKGROUND_BLACK,
VIDEO_MIXER2_BACKGROUND_WHITE
VIDEO_MIXER2_BACKGROUND_WHITE,
VIDEO_MIXER2_BACKGROUND_TRANSPARENT,
}
GstVideoMixer2Background;
@ -106,7 +108,7 @@ struct _GstVideoMixer2
GstClockTime earliest_time;
guint64 qos_processed, qos_dropped;
BlendFunction blend;
BlendFunction blend, overlay;
FillCheckerFunction fill_checker;
FillColorFunction fill_color;
};