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Merged
naushir merged 2 commits into from
Jul 30, 2026
Merged

RGB fixes #77

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8850470
gst: Fix R/B channel ordering for RGB output formats
naushir Jul 28, 2026
21a2954
tests: Drop BGR compensation for GStreamer RGB output
naushir Jul 28, 2026
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41 changes: 29 additions & 12 deletions src/gst/gstpispconvert.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ GST_ELEMENT_REGISTER_DEFINE(pispconvert, "pispconvert", GST_RANK_PRIMARY, GST_TY
static const std::map<GstVideoFormat, std::string> gst_pisp_format_map = {
{ GST_VIDEO_FORMAT_RGB, "RGB888" },
{ GST_VIDEO_FORMAT_RGBx, "RGBX8888" },
{ GST_VIDEO_FORMAT_BGRx, "XRGB8888" },
{ GST_VIDEO_FORMAT_BGRx, "RGBX8888" },
{ GST_VIDEO_FORMAT_I420, "YUV420P" },
{ GST_VIDEO_FORMAT_YV12, "YVU420P" },
{ GST_VIDEO_FORMAT_Y42B, "YUV422P" },
Expand All @@ -84,7 +84,7 @@ static const std::map<std::string, std::string> drm_pisp_format_map = {
{ "RG24", "RGB888" },
{ "BG24", "RGB888" },
{ "XB24", "RGBX8888" },
{ "XR24", "XRGB8888" },
{ "XR24", "RGBX8888" },
{ "YU12", "YUV420P" },
{ "YV12", "YVU420P" },
{ "YU16", "YUV422P" },
Expand All @@ -96,20 +96,33 @@ static const std::map<std::string, std::string> drm_pisp_format_map = {
{ "P030:0x0700000000000004", "YUV420SP10_COL128" },
};

/* Formats storing channels in B,G,R memory order need an R/B swap relative to
* the hardware's native R,G,B channel output. Keyed on the GStreamer/DRM
* format as the PiSP format string does not encode the channel order. */
static bool require_rb_swap(GstVideoFormat format)
{
return format == GST_VIDEO_FORMAT_BGRx;
}

static bool require_rb_swap(const gchar *drm_format)
{
return drm_format && (g_str_equal(drm_format, "XR24") || g_str_equal(drm_format, "RG24"));
}

static const char *gst_format_to_pisp(GstVideoFormat format)
{
auto it = gst_pisp_format_map.find(format);
return it != gst_pisp_format_map.end() ? it->second.c_str() : nullptr;
}

static GstVideoFormat pisp_to_gst_video_format(const char *pisp_format)
static GstVideoFormat pisp_to_gst_video_format(const char *pisp_format, bool rb_swap)
{
if (!pisp_format)
return GST_VIDEO_FORMAT_UNKNOWN;

for (const auto &[gst_fmt, pisp_fmt] : gst_pisp_format_map)
{
if (g_str_equal(pisp_format, pisp_fmt.c_str()))
if (g_str_equal(pisp_format, pisp_fmt.c_str()) && rb_swap == require_rb_swap(gst_fmt))
return gst_fmt;
}
return GST_VIDEO_FORMAT_UNKNOWN;
Expand Down Expand Up @@ -153,7 +166,7 @@ static const char *colorimetry_to_pisp(const GstVideoColorimetry *colorimetry)

/* Configure colour space conversion blocks for the backend */
static uint32_t configure_colour_conversion(libpisp::BackEnd *backend, const char *in_format, const char *in_colorspace,
const char *out_format, const char *out_colorspace,
const char *out_format, bool out_rb_swap, const char *out_colorspace,
unsigned int output_index)
{
uint32_t rgb_enables = 0;
Expand All @@ -175,8 +188,7 @@ static uint32_t configure_colour_conversion(libpisp::BackEnd *backend, const cha
backend->SetCsc(output_index, csc);
rgb_enables |= PISP_BE_RGB_ENABLE_CSC(output_index);
}
else if (g_str_equal(out_format, "RGB888") || g_str_equal(out_format, "RGBX8888") ||
g_str_equal(out_format, "XRGB8888"))
else if (out_rb_swap)
{
/* R/B channel swap to match GStreamer/DRM byte ordering */
pisp_be_ccm_config csc = {};
Expand Down Expand Up @@ -371,6 +383,7 @@ static void gst_pisp_convert_init(GstPispConvert *self)
self->priv->out_stride[i] = 0;
self->priv->out_hw_stride[i] = 0;
self->priv->out_format[i] = nullptr;
self->priv->out_rb_swap[i] = false;
self->priv->output_enabled[i] = FALSE;
self->priv->use_dmabuf_output[i] = FALSE;
self->priv->output_pool[i] = nullptr;
Expand Down Expand Up @@ -447,6 +460,7 @@ static gboolean parse_output_caps(GstPispConvert *self, guint index, GstCaps *ca
gst_structure_get_int(out_structure, "width", (gint *)&self->priv->out_width[index]);
gst_structure_get_int(out_structure, "height", (gint *)&self->priv->out_height[index]);
self->priv->out_format[index] = drm_format_to_pisp(drm_format);
self->priv->out_rb_swap[index] = require_rb_swap(drm_format);
self->priv->out_stride[index] = 0;

GstVideoColorimetry colorimetry = {};
Expand All @@ -470,6 +484,7 @@ static gboolean parse_output_caps(GstPispConvert *self, guint index, GstCaps *ca
self->priv->out_height[index] = GST_VIDEO_INFO_HEIGHT(&out_info);
self->priv->out_stride[index] = GST_VIDEO_INFO_PLANE_STRIDE(&out_info, 0);
self->priv->out_format[index] = gst_format_to_pisp(GST_VIDEO_INFO_FORMAT(&out_info));
self->priv->out_rb_swap[index] = require_rb_swap(GST_VIDEO_INFO_FORMAT(&out_info));
self->priv->out_colorspace[index] = colorimetry_to_pisp(&GST_VIDEO_INFO_COLORIMETRY(&out_info));
GST_INFO_OBJECT(self, "Output%u format: pisp=%s, colorspace=%s (matrix=%d, range=%d)", index,
self->priv->out_format[index], self->priv->out_colorspace[index],
Expand Down Expand Up @@ -637,9 +652,10 @@ static GstBuffer *libpisp_to_gst_dmabuf(const Buffer &buffer, GstAllocator *dmab
}

/* Attach GstVideoMeta with the correct hardware stride to a dmabuf output buffer */
static void add_video_meta(GstBuffer *buffer, const char *pisp_format, guint width, guint height, guint hw_stride)
static void add_video_meta(GstBuffer *buffer, const char *pisp_format, bool rb_swap, guint width, guint height,
guint hw_stride)
{
GstVideoFormat gst_fmt = pisp_to_gst_video_format(pisp_format);
GstVideoFormat gst_fmt = pisp_to_gst_video_format(pisp_format, rb_swap);
if (gst_fmt == GST_VIDEO_FORMAT_UNKNOWN)
return;

Expand Down Expand Up @@ -889,7 +905,8 @@ static gboolean gst_pisp_convert_configure(GstPispConvert *self)

global.rgb_enables |= configure_colour_conversion(self->priv->backend.get(), self->priv->in_format,
self->priv->in_colorspace, self->priv->out_format[i],
self->priv->out_colorspace[i], i);
self->priv->out_rb_swap[i], self->priv->out_colorspace[i],
i);

GST_INFO_OBJECT(self, "Output%d: %ux%u %s (stride: gst=%u hw=%u) colorspace %s", i,
self->priv->out_width[i], self->priv->out_height[i], self->priv->out_format[i],
Expand Down Expand Up @@ -1135,8 +1152,8 @@ static GstFlowReturn gst_pisp_convert_chain(GstPad *pad [[maybe_unused]], GstObj
goto cleanup;
}

add_video_meta(outbuf[i], self->priv->out_format[i], self->priv->out_width[i], self->priv->out_height[i],
self->priv->out_hw_stride[i]);
add_video_meta(outbuf[i], self->priv->out_format[i], self->priv->out_rb_swap[i], self->priv->out_width[i],
self->priv->out_height[i], self->priv->out_hw_stride[i]);

GST_DEBUG_OBJECT(self, "Using zero-copy output%d path", i);
}
Expand Down
1 change: 1 addition & 0 deletions src/gst/gstpispconvert.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,7 @@ struct _GstPispConvertPrivate
guint out_hw_stride[PISP_NUM_OUTPUTS]; // Hardware buffer stride
const char *out_format[PISP_NUM_OUTPUTS];
const char *out_colorspace[PISP_NUM_OUTPUTS];
bool out_rb_swap[PISP_NUM_OUTPUTS]; // Memory stores B,G,R channel order
gboolean output_enabled[PISP_NUM_OUTPUTS]; // Track which outputs are active

/* dmabuf support */
Expand Down
6 changes: 0 additions & 6 deletions utils/test_convert.py
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Expand Up @@ -106,8 +106,6 @@ def run_gstreamer(self, input_file, output_file, input_format, output_format):
# Convert to GStreamer format names
gst_in_format = self._pisp_to_gst_format(in_fmt["format"])
gst_out_format = self._pisp_to_gst_format(out_fmt["format"])
# pispconvert swaps R/B for RGB, use BGR file output to match convert reference
gst_file_format = "BGR" if gst_out_format == "RGB" else gst_out_format

# Build GStreamer pipeline
pipeline = [
Expand All @@ -127,10 +125,6 @@ def run_gstreamer(self, input_file, output_file, input_format, output_format):
"!",
f"video/x-raw,format={gst_out_format},width={out_fmt['width']},height={out_fmt['height']},colorimetry=1:4:0:0",
"!",
"videoconvert",
"!",
f"video/x-raw,format={gst_file_format},width={out_fmt['width']},height={out_fmt['height']}",
"!",
"filesink",
f"location={output_file}",
]
Expand Down
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