avfilter/thumbnail_cuda: add cuda thumbnail filter

Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>

5 files changed, 526 insertions, 1 deletions

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 8aa974e115..98acb51bcb 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -315,6 +315,7 @@ OBJS-$(CONFIG_TBLEND_FILTER)                 += vf_blend.o framesync.o
 OBJS-$(CONFIG_TELECINE_FILTER)               += vf_telecine.o
 OBJS-$(CONFIG_THRESHOLD_FILTER)              += vf_threshold.o framesync.o
 OBJS-$(CONFIG_THUMBNAIL_FILTER)              += vf_thumbnail.o
+OBJS-$(CONFIG_THUMBNAIL_CUDA_FILTER)         += vf_thumbnail_cuda.o vf_thumbnail_cuda.ptx.o
 OBJS-$(CONFIG_TILE_FILTER)                   += vf_tile.o
 OBJS-$(CONFIG_TINTERLACE_FILTER)             += vf_tinterlace.o
 OBJS-$(CONFIG_TLUT2_FILTER)                  += vf_lut2.o framesync.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 63e86721cd..baa84a3e72 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -326,6 +326,7 @@ static void register_all(void)
     REGISTER_FILTER(TELECINE,       telecine,       vf);
     REGISTER_FILTER(THRESHOLD,      threshold,      vf);
     REGISTER_FILTER(THUMBNAIL,      thumbnail,      vf);
+    REGISTER_FILTER(THUMBNAIL_CUDA, thumbnail_cuda, vf);
     REGISTER_FILTER(TILE,           tile,           vf);
     REGISTER_FILTER(TINTERLACE,     tinterlace,     vf);
     REGISTER_FILTER(TLUT2,          tlut2,          vf);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 5d6aa5fc70..fb382d4e25 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR 105
+#define LIBAVFILTER_VERSION_MINOR 106
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/vf_thumbnail_cuda.c b/libavfilter/vf_thumbnail_cuda.c
new file mode 100644
index 0000000000..4c08a85121
--- /dev/null
+++ b/libavfilter/vf_thumbnail_cuda.c
@@ -0,0 +1,444 @@
+/*
+* Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+* DEALINGS IN THE SOFTWARE.
+*/
+
+#include <cuda.h>
+
+#include "libavutil/hwcontext.h"
+#include "libavutil/hwcontext_cuda_internal.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+
+#include "avfilter.h"
+#include "internal.h"
+
+#define HIST_SIZE (3*256)
+#define DIV_UP(a, b) ( ((a) + (b) - 1) / (b) )
+#define BLOCKX 32
+#define BLOCKY 16
+
+static const enum AVPixelFormat supported_formats[] = {
+    AV_PIX_FMT_NV12,
+    AV_PIX_FMT_YUV420P,
+    AV_PIX_FMT_YUV444P,
+    AV_PIX_FMT_P010,
+    AV_PIX_FMT_P016,
+    AV_PIX_FMT_YUV444P16,
+};
+
+struct thumb_frame {
+    AVFrame *buf;               ///< cached frame
+    int histogram[HIST_SIZE];   ///< RGB color distribution histogram of the frame
+};
+
+typedef struct ThumbnailCudaContext {
+    const AVClass *class;
+    int n;                      ///< current frame
+    int n_frames;               ///< number of frames for analysis
+    struct thumb_frame *frames; ///< the n_frames frames
+    AVRational tb;              ///< copy of the input timebase to ease access
+
+    AVBufferRef *hw_frames_ctx;
+
+    CUmodule    cu_module;
+
+    CUfunction  cu_func_uchar;
+    CUfunction  cu_func_uchar2;
+    CUfunction  cu_func_ushort;
+    CUfunction  cu_func_ushort2;
+    CUtexref    cu_tex_uchar;
+    CUtexref    cu_tex_uchar2;
+    CUtexref    cu_tex_ushort;
+    CUtexref    cu_tex_ushort2;
+
+    CUdeviceptr data;
+} ThumbnailCudaContext;
+
+#define OFFSET(x) offsetof(ThumbnailCudaContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption thumbnail_cuda_options[] = {
+    { "n", "set the frames batch size", OFFSET(n_frames), AV_OPT_TYPE_INT, {.i64=100}, 2, INT_MAX, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(thumbnail_cuda);
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    ThumbnailCudaContext *s = ctx->priv;
+
+    s->frames = av_calloc(s->n_frames, sizeof(*s->frames));
+    if (!s->frames) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Allocation failure, try to lower the number of frames\n");
+        return AVERROR(ENOMEM);
+    }
+    av_log(ctx, AV_LOG_VERBOSE, "batch size: %d frames\n", s->n_frames);
+    return 0;
+}
+
+/**
+ * @brief        Compute Sum-square deviation to estimate "closeness".
+ * @param hist   color distribution histogram
+ * @param median average color distribution histogram
+ * @return       sum of squared errors
+ */
+static double frame_sum_square_err(const int *hist, const double *median)
+{
+    int i;
+    double err, sum_sq_err = 0;
+
+    for (i = 0; i < HIST_SIZE; i++) {
+        err = median[i] - (double)hist[i];
+        sum_sq_err += err*err;
+    }
+    return sum_sq_err;
+}
+
+static AVFrame *get_best_frame(AVFilterContext *ctx)
+{
+    AVFrame *picref;
+    ThumbnailCudaContext *s = ctx->priv;
+    int i, j, best_frame_idx = 0;
+    int nb_frames = s->n;
+    double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1;
+
+    // average histogram of the N frames
+    for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) {
+        for (i = 0; i < nb_frames; i++)
+            avg_hist[j] += (double)s->frames[i].histogram[j];
+        avg_hist[j] /= nb_frames;
+    }
+
+    // find the frame closer to the average using the sum of squared errors
+    for (i = 0; i < nb_frames; i++) {
+        sq_err = frame_sum_square_err(s->frames[i].histogram, avg_hist);
+        if (i == 0 || sq_err < min_sq_err)
+            best_frame_idx = i, min_sq_err = sq_err;
+    }
+
+    // free and reset everything (except the best frame buffer)
+    for (i = 0; i < nb_frames; i++) {
+        memset(s->frames[i].histogram, 0, sizeof(s->frames[i].histogram));
+        if (i != best_frame_idx)
+            av_frame_free(&s->frames[i].buf);
+    }
+    s->n = 0;
+
+    // raise the chosen one
+    picref = s->frames[best_frame_idx].buf;
+    av_log(ctx, AV_LOG_INFO, "frame id #%d (pts_time=%f) selected "
+           "from a set of %d images\n", best_frame_idx,
+           picref->pts * av_q2d(s->tb), nb_frames);
+    s->frames[best_frame_idx].buf = NULL;
+
+    return picref;
+}
+
+static int thumbnail_kernel(ThumbnailCudaContext *s, CUfunction func, CUtexref tex, int channels,
+    int *histogram, uint8_t *src_dptr, int src_width, int src_height, int src_pitch, int pixel_size)
+{
+    CUdeviceptr src_devptr = (CUdeviceptr)src_dptr;
+    void *args[] = { &histogram, &src_width, &src_height };
+    CUDA_ARRAY_DESCRIPTOR desc;
+
+    desc.Width = src_width;
+    desc.Height = src_height;
+    desc.NumChannels = channels;
+    if (pixel_size == 1) {
+        desc.Format = CU_AD_FORMAT_UNSIGNED_INT8;
+    }
+    else {
+        desc.Format = CU_AD_FORMAT_UNSIGNED_INT16;
+    }
+
+    cuTexRefSetAddress2D_v3(tex, &desc, src_devptr, src_pitch);
+    cuLaunchKernel(func, DIV_UP(src_width, BLOCKX), DIV_UP(src_height, BLOCKY), 1, BLOCKX, BLOCKY, 1, 0, 0, args, NULL);
+
+    return 0;
+}
+
+static int thumbnail(AVFilterContext *ctx, int *histogram, AVFrame *in)
+{
+    AVHWFramesContext *in_frames_ctx = (AVHWFramesContext*)in->hw_frames_ctx->data;
+    ThumbnailCudaContext *s = ctx->priv;
+
+    switch (in_frames_ctx->sw_format) {
+    case AV_PIX_FMT_NV12:
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
+        thumbnail_kernel(s, s->cu_func_uchar2, s->cu_tex_uchar2, 2,
+            histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 1);
+        break;
+    case AV_PIX_FMT_YUV420P:
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 1);
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram + 512, in->data[2], in->width / 2, in->height / 2, in->linesize[2], 1);
+        break;
+    case AV_PIX_FMT_YUV444P:
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram + 256, in->data[1], in->width, in->height, in->linesize[1], 1);
+        thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
+            histogram + 512, in->data[2], in->width, in->height, in->linesize[2], 1);
+        break;
+    case AV_PIX_FMT_P010LE:
+    case AV_PIX_FMT_P016LE:
+        thumbnail_kernel(s, s->cu_func_ushort, s->cu_tex_ushort, 1,
+            histogram, in->data[0], in->width, in->height, in->linesize[0], 2);
+        thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_ushort2, 2,
+            histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 2);
+        break;
+    case AV_PIX_FMT_YUV444P16:
+        thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
+            histogram, in->data[0], in->width, in->height, in->linesize[0], 2);
+        thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
+            histogram + 256, in->data[1], in->width, in->height, in->linesize[1], 2);
+        thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
+            histogram + 512, in->data[2], in->width, in->height, in->linesize[2], 2);
+        break;
+    default:
+        return AVERROR_BUG;
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx  = inlink->dst;
+    ThumbnailCudaContext *s   = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    int *hist = s->frames[s->n].histogram;
+    AVHWFramesContext *hw_frames_ctx = (AVHWFramesContext*)s->hw_frames_ctx->data;
+    AVCUDADeviceContext *device_hwctx = hw_frames_ctx->device_ctx->hwctx;
+    CUresult err;
+    CUcontext dummy;
+    CUDA_MEMCPY2D cpy = { 0 };
+    int ret = 0;
+
+    // keep a reference of each frame
+    s->frames[s->n].buf = frame;
+
+    err = cuCtxPushCurrent(device_hwctx->cuda_ctx);
+    if (err != CUDA_SUCCESS)
+        return AVERROR_UNKNOWN;
+
+    cuMemsetD8(s->data, 0, HIST_SIZE * sizeof(int));
+
+    thumbnail(ctx, (int*)s->data, frame);
+
+    cpy.srcMemoryType = CU_MEMORYTYPE_DEVICE;
+    cpy.dstMemoryType = CU_MEMORYTYPE_HOST;
+    cpy.srcDevice = s->data;
+    cpy.dstHost = hist;
+    cpy.srcPitch = HIST_SIZE * sizeof(int);
+    cpy.dstPitch = HIST_SIZE * sizeof(int);
+    cpy.WidthInBytes = HIST_SIZE * sizeof(int);
+    cpy.Height = 1;
+
+    err = cuMemcpy2D(&cpy);
+    if (err != CUDA_SUCCESS) {
+        av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    if (hw_frames_ctx->sw_format == AV_PIX_FMT_NV12 || hw_frames_ctx->sw_format == AV_PIX_FMT_YUV420P ||
+        hw_frames_ctx->sw_format == AV_PIX_FMT_P010LE || hw_frames_ctx->sw_format == AV_PIX_FMT_P016LE)
+    {
+        for (int i = 256; i < HIST_SIZE; i++)
+            hist[i] = 4 * hist[i];
+    }
+
+    cuCtxPopCurrent(&dummy);
+    if (ret < 0)
+        return ret;
+
+    // no selection until the buffer of N frames is filled up
+    s->n++;
+    if (s->n < s->n_frames)
+        return 0;
+
+    return ff_filter_frame(outlink, get_best_frame(ctx));
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    int i;
+    ThumbnailCudaContext *s = ctx->priv;
+
+    if (s->data) {
+        cuMemFree(s->data);
+        s->data = 0;
+    }
+
+    if (s->cu_module) {
+        cuModuleUnload(s->cu_module);
+        s->cu_module = NULL;
+    }
+
+    for (i = 0; i < s->n_frames && s->frames[i].buf; i++)
+        av_frame_free(&s->frames[i].buf);
+    av_freep(&s->frames);
+}
+
+static int request_frame(AVFilterLink *link)
+{
+    AVFilterContext *ctx = link->src;
+    ThumbnailCudaContext *s = ctx->priv;
+    int ret = ff_request_frame(ctx->inputs[0]);
+
+    if (ret == AVERROR_EOF && s->n) {
+        ret = ff_filter_frame(link, get_best_frame(ctx));
+        if (ret < 0)
+            return ret;
+        ret = AVERROR_EOF;
+    }
+    if (ret < 0)
+        return ret;
+    return 0;
+}
+
+static int format_is_supported(enum AVPixelFormat fmt)
+{
+    int i;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++)
+        if (supported_formats[i] == fmt)
+            return 1;
+    return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ThumbnailCudaContext *s = ctx->priv;
+    AVHWFramesContext     *hw_frames_ctx = (AVHWFramesContext*)inlink->hw_frames_ctx->data;
+    AVCUDADeviceContext *device_hwctx = hw_frames_ctx->device_ctx->hwctx;
+    CUcontext dummy, cuda_ctx = device_hwctx->cuda_ctx;
+    CUresult err;
+
+    extern char vf_thumbnail_cuda_ptx[];
+
+    err = cuCtxPushCurrent(cuda_ctx);
+    if (err != CUDA_SUCCESS) {
+        av_log(ctx, AV_LOG_ERROR, "Error pushing cuda context\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    err = cuModuleLoadData(&s->cu_module, vf_thumbnail_cuda_ptx);
+    if (err != CUDA_SUCCESS) {
+        av_log(ctx, AV_LOG_ERROR, "Error loading module data\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    cuModuleGetFunction(&s->cu_func_uchar, s->cu_module, "Thumbnail_uchar");
+    cuModuleGetFunction(&s->cu_func_uchar2, s->cu_module, "Thumbnail_uchar2");
+    cuModuleGetFunction(&s->cu_func_ushort, s->cu_module, "Thumbnail_ushort");
+    cuModuleGetFunction(&s->cu_func_ushort2, s->cu_module, "Thumbnail_ushort2");
+
+    cuModuleGetTexRef(&s->cu_tex_uchar, s->cu_module, "uchar_tex");
+    cuModuleGetTexRef(&s->cu_tex_uchar2, s->cu_module, "uchar2_tex");
+    cuModuleGetTexRef(&s->cu_tex_ushort, s->cu_module, "ushort_tex");
+    cuModuleGetTexRef(&s->cu_tex_ushort2, s->cu_module, "ushort2_tex");
+
+    cuTexRefSetFlags(s->cu_tex_uchar, CU_TRSF_READ_AS_INTEGER);
+    cuTexRefSetFlags(s->cu_tex_uchar2, CU_TRSF_READ_AS_INTEGER);
+    cuTexRefSetFlags(s->cu_tex_ushort, CU_TRSF_READ_AS_INTEGER);
+    cuTexRefSetFlags(s->cu_tex_ushort2, CU_TRSF_READ_AS_INTEGER);
+
+    cuTexRefSetFilterMode(s->cu_tex_uchar, CU_TR_FILTER_MODE_LINEAR);
+    cuTexRefSetFilterMode(s->cu_tex_uchar2, CU_TR_FILTER_MODE_LINEAR);
+    cuTexRefSetFilterMode(s->cu_tex_ushort, CU_TR_FILTER_MODE_LINEAR);
+    cuTexRefSetFilterMode(s->cu_tex_ushort2, CU_TR_FILTER_MODE_LINEAR);
+
+    err = cuMemAlloc(&s->data, HIST_SIZE * sizeof(int));
+    if (err != CUDA_SUCCESS) {
+        av_log(ctx, AV_LOG_ERROR, "Error allocating cuda memory\n");
+        return AVERROR_UNKNOWN;
+    }
+
+    cuCtxPopCurrent(&dummy);
+
+    s->hw_frames_ctx = ctx->inputs[0]->hw_frames_ctx;
+
+    ctx->outputs[0]->hw_frames_ctx = av_buffer_ref(s->hw_frames_ctx);
+    if (!ctx->outputs[0]->hw_frames_ctx)
+        return AVERROR(ENOMEM);
+
+    s->tb = inlink->time_base;
+
+    if (!format_is_supported(hw_frames_ctx->sw_format)) {
+        av_log(ctx, AV_LOG_ERROR, "Unsupported input format: %s\n", av_get_pix_fmt_name(hw_frames_ctx->sw_format));
+        return AVERROR(ENOSYS);
+    }
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_CUDA,
+        AV_PIX_FMT_NONE
+    };
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+static const AVFilterPad thumbnail_cuda_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_props,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad thumbnail_cuda_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_thumbnail_cuda = {
+    .name          = "thumbnail_cuda",
+    .description   = NULL_IF_CONFIG_SMALL("Select the most representative frame in a given sequence of consecutive frames."),
+    .priv_size     = sizeof(ThumbnailCudaContext),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = thumbnail_cuda_inputs,
+    .outputs       = thumbnail_cuda_outputs,
+    .priv_class    = &thumbnail_cuda_class,
+    .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
+};
diff --git a/libavfilter/vf_thumbnail_cuda.cu b/libavfilter/vf_thumbnail_cuda.cu
new file mode 100644
index 0000000000..98fad4303a
--- /dev/null
+++ b/libavfilter/vf_thumbnail_cuda.cu
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+extern "C" {
+
+texture<unsigned char, 2> uchar_tex;
+texture<uchar2, 2>  uchar2_tex;
+texture<unsigned short, 2> ushort_tex;
+texture<ushort2, 2>  ushort2_tex;
+
+__global__ void Thumbnail_uchar(int *histogram, int src_width, int src_height)
+{
+    int x = blockIdx.x * blockDim.x + threadIdx.x;
+    int y = blockIdx.y * blockDim.y + threadIdx.y;
+    if (y < src_height && x < src_width)
+    {
+        unsigned char pixel = tex2D(uchar_tex, x, y);
+        atomicAdd(&histogram[pixel], 1);
+    }
+}
+
+__global__ void Thumbnail_uchar2(int *histogram, int src_width, int src_height)
+{
+    int x = blockIdx.x * blockDim.x + threadIdx.x;
+    int y = blockIdx.y * blockDim.y + threadIdx.y;
+
+    if (y < src_height && x < src_width)
+    {
+        uchar2 pixel = tex2D(uchar2_tex, x, y);
+        atomicAdd(&histogram[pixel.x], 1);
+        atomicAdd(&histogram[256 + pixel.y], 1);
+    }
+}
+
+__global__ void Thumbnail_ushort(int *histogram, int src_width, int src_height)
+{
+    int x = blockIdx.x * blockDim.x + threadIdx.x;
+    int y = blockIdx.y * blockDim.y + threadIdx.y;
+
+    if (y < src_height && x < src_width)
+    {
+        unsigned short pixel = (tex2D(ushort_tex, x, y) + 128) >> 8;
+        atomicAdd(&histogram[pixel], 1);
+    }
+}
+
+__global__ void Thumbnail_ushort2(int *histogram, int src_width, int src_height)
+{
+    int x = blockIdx.x * blockDim.x + threadIdx.x;
+    int y = blockIdx.y * blockDim.y + threadIdx.y;
+
+    if (y < src_height && x < src_width)
+    {
+        ushort2 pixel = tex2D(ushort2_tex, x, y);
+        atomicAdd(&histogram[(pixel.x + 128) >> 8], 1);
+        atomicAdd(&histogram[256 + (pixel.y + 128) >> 8], 1);
+    }
+}
+
+}