gofair做网站,wordpress的文章tag标签,1000M双线网站空间,html5网站开发视频降噪
视频降噪是一种处理技术#xff0c;旨在减少视频中的噪声#xff0c;提高画面质量。噪声可能来自多种源头#xff0c;包括摄像机的传感器、压缩算法、传输过程中的干扰等。降噪处理对于视频监控、视频会议、电影后期制作以及任何需要高画质输出的应用场景都非常重…视频降噪
视频降噪是一种处理技术旨在减少视频中的噪声提高画面质量。噪声可能来自多种源头包括摄像机的传感器、压缩算法、传输过程中的干扰等。降噪处理对于视频监控、视频会议、电影后期制作以及任何需要高画质输出的应用场景都非常重要。
视频降噪技术通常包括以下几个关键点 时域降噪利用连续视频帧之间的时间冗余通过分析连续帧中相同位置像素的变化来识别噪声并进行相应的处理。 空域降噪在单帧视频内通过分析像素邻域内的亮度和色度信息来识别并减少噪声。 3D降噪结合时域和空域信息同时考虑视频帧的当前帧和相邻帧进行更加复杂的降噪处理。 非线性降噪某些算法采用非线性处理方法如中值滤波或维纳滤波来减少噪声这些方法对某些类型的噪声特别有效。 自适应降噪根据视频内容的复杂性和噪声水平动态调整降噪强度。 基于模型的降噪使用统计模型或机器学习技术来识别噪声模式并进行相应的降噪处理。 运动补偿在视频中运动物体的噪声处理需要特别考虑以避免在运动补偿过程中引入伪影。 硬件加速某些降噪算法可以在GPU或其他专用硬件上执行以提高处理速度。 用户控制许多降噪工具提供用户界面允许用户根据需要调整降噪参数。
关于视频降噪的算法综述可以参考视频降噪综述。
hqdn3d
hqdn3dHigh Quality 3D Denoise是一种高质量的三维视频降噪算法主要用于去除视频中的噪声。hqdn3d算法能够有效地去除视频中的高频率噪声同时尽量减少图像的失真和模糊保持视频质量。
hqdn3d算法已经被实现为AviSynth插件并且可以在FFmpeg中作为滤镜使用例如通过命令 ffmpeg -i input.avi -vf hqdn3d output.mp4 来应用。高质量去噪3D是一个AviSynth端口的同名MPlayer过滤器。采用3路低通滤波在完全去除高频噪声的同时最大限度地减少混合伪影。 在AviSynth中使用 hqdn3d 方法如下有对应的空域滤波、时域滤波的亮度和色度强度设置参数。 AviSynth官网http://www.avisynth.org/ FFmpeg 官网https://ffmpeg.org/
原理
hqdn3d 算法的原理相对比较容易理解总结其原理如下
该算法是像素处理不涉及频域和运动搜索空域去噪时当前像素参考当前帧左邻、上邻和前一帧同一位置的像素对每个像素多次应用低通滤波器时域去噪时参考前一帧同一位置的像素对每个像素应用一个低通滤波器根据相邻像素的差确定偏移量将相邻像素颜色值“拉近”即对像素做加减法以达到降噪目的对于较小的像素差异hqdn3d会拉近距离若差异较大降低偏置系数达到保边效果可以通过外部设置滤波强度调整峰值位置
分析 FFmpeg 中 hqdn3d 算法算法实现流程如下
源码
FFmpeg 中 filter 滤镜对应的 hqdn3d 算法实现
/** Copyright (c) 2003 Daniel Moreno comac AT comac DOT darktech DOT org* Copyright (c) 2010 Baptiste Coudurier* Copyright (c) 2012 Loren Merritt** This file is part of FFmpeg, ported from MPlayer.** FFmpeg is free software; you can redistribute it and/or modify* it under the terms of the GNU General Public License as published by* the Free Software Foundation; either version 2 of the License, or* (at your option) any later version.** FFmpeg is distributed in the hope that it will be useful,* but WITHOUT ANY WARRANTY; without even the implied warranty of* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the* GNU General Public License for more details.** You should have received a copy of the GNU General Public License along* with FFmpeg; if not, write to the Free Software Foundation, Inc.,* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.*//*** file* high quality 3d video denoiser, ported from MPlayer* libmpcodecs/vf_hqdn3d.c.*/#include float.h#include config.h
#include libavutil/attributes.h
#include libavutil/common.h
#include libavutil/pixdesc.h
#include libavutil/intreadwrite.h
#include libavutil/opt.h#include avfilter.h
#include formats.h
#include internal.h
#include video.h
#include vf_hqdn3d.h#define LUT_BITS (depth16 ? 8 : 4)
#define LOAD(x) (((depth 8 ? src[x] : AV_RN16A(src (x) * 2)) (16 - depth))\ (((1 (16 - depth)) - 1) 1))
#define STORE(x,val) (depth 8 ? dst[x] (val) (16 - depth) : \AV_WN16A(dst (x) * 2, (val) (16 - depth)))av_always_inline
static uint32_t lowpass(int prev, int cur, int16_t *coef, int depth)
{int d (prev - cur) (8 - LUT_BITS);return cur coef[d];
}av_always_inline
static void denoise_temporal(uint8_t *src, uint8_t *dst,uint16_t *frame_ant,int w, int h, int sstride, int dstride,int16_t *temporal, int depth)
{long x, y;uint32_t tmp;temporal 256 LUT_BITS;for (y 0; y h; y) {for (x 0; x w; x) {frame_ant[x] tmp lowpass(frame_ant[x], LOAD(x), temporal, depth);STORE(x, tmp);}src sstride;dst dstride;frame_ant w;}
}av_always_inline
static void denoise_spatial(HQDN3DContext *s,uint8_t *src, uint8_t *dst,uint16_t *line_ant, uint16_t *frame_ant,int w, int h, int sstride, int dstride,int16_t *spatial, int16_t *temporal, int depth)
{long x, y;uint32_t pixel_ant;uint32_t tmp;spatial 256 LUT_BITS;temporal 256 LUT_BITS;/* First line has no top neighbor. Only left one for each tmp and* last frame */pixel_ant LOAD(0);for (x 0; x w; x) {line_ant[x] tmp pixel_ant lowpass(pixel_ant, LOAD(x), spatial, depth);frame_ant[x] tmp lowpass(frame_ant[x], tmp, temporal, depth);STORE(x, tmp);}for (y 1; y h; y) {src sstride;dst dstride;frame_ant w;if (s-denoise_row[depth]) {s-denoise_row[depth](src, dst, line_ant, frame_ant, w, spatial, temporal);continue;}pixel_ant LOAD(0);for (x 0; x w-1; x) {line_ant[x] tmp lowpass(line_ant[x], pixel_ant, spatial, depth);pixel_ant lowpass(pixel_ant, LOAD(x1), spatial, depth);frame_ant[x] tmp lowpass(frame_ant[x], tmp, temporal, depth);STORE(x, tmp);}line_ant[x] tmp lowpass(line_ant[x], pixel_ant, spatial, depth);frame_ant[x] tmp lowpass(frame_ant[x], tmp, temporal, depth);STORE(x, tmp);}
}av_always_inline
static int denoise_depth(HQDN3DContext *s,uint8_t *src, uint8_t *dst,uint16_t *line_ant, uint16_t **frame_ant_ptr,int w, int h, int sstride, int dstride,int16_t *spatial, int16_t *temporal, int depth)
{// FIXME: For 16-bit depth, frame_ant could be a pointer to the previous// filtered frame rather than a separate buffer.long x, y;uint16_t *frame_ant *frame_ant_ptr;if (!frame_ant) {uint8_t *frame_src src;*frame_ant_ptr frame_ant av_malloc_array(w, h*sizeof(uint16_t));if (!frame_ant)return AVERROR(ENOMEM);for (y 0; y h; y, src sstride, frame_ant w)for (x 0; x w; x)frame_ant[x] LOAD(x);src frame_src;frame_ant *frame_ant_ptr;}if (spatial[0])denoise_spatial(s, src, dst, line_ant, frame_ant,w, h, sstride, dstride, spatial, temporal, depth);elsedenoise_temporal(src, dst, frame_ant,w, h, sstride, dstride, temporal, depth);emms_c();return 0;
}#define denoise(...) \do { \int ret AVERROR_BUG; \switch (s-depth) { \case 8: ret denoise_depth(__VA_ARGS__, 8); break; \case 9: ret denoise_depth(__VA_ARGS__, 9); break; \case 10: ret denoise_depth(__VA_ARGS__, 10); break; \case 12: ret denoise_depth(__VA_ARGS__, 12); break; \case 14: ret denoise_depth(__VA_ARGS__, 14); break; \case 16: ret denoise_depth(__VA_ARGS__, 16); break; \} \if (ret 0) { \av_frame_free(out); \if (!direct) \av_frame_free(in); \return ret; \} \} while (0)static void precalc_coefs(double dist25, int depth, int16_t *ct)
{int i;double gamma, simil, C;gamma log(0.25) / log(1.0 - FFMIN(dist25,252.0)/255.0 - 0.00001);for (i -256LUT_BITS; i 256LUT_BITS; i) {double f ((i(9-LUT_BITS)) (1(8-LUT_BITS)) - 1) / 512.0; // midpoint of the binsimil FFMAX(0, 1.0 - fabs(f) / 255.0);C pow(simil, gamma) * 256.0 * f;ct[(256LUT_BITS)i] lrint(C);}ct[0] !!dist25;
}#define PARAM1_DEFAULT 4.0
#define PARAM2_DEFAULT 3.0
#define PARAM3_DEFAULT 6.0static av_cold int init(AVFilterContext *ctx)
{HQDN3DContext *s ctx-priv;if (!s-strength[LUMA_SPATIAL])s-strength[LUMA_SPATIAL] PARAM1_DEFAULT;if (!s-strength[CHROMA_SPATIAL])s-strength[CHROMA_SPATIAL] PARAM2_DEFAULT * s-strength[LUMA_SPATIAL] / PARAM1_DEFAULT;if (!s-strength[LUMA_TMP])s-strength[LUMA_TMP] PARAM3_DEFAULT * s-strength[LUMA_SPATIAL] / PARAM1_DEFAULT;if (!s-strength[CHROMA_TMP])s-strength[CHROMA_TMP] s-strength[LUMA_TMP] * s-strength[CHROMA_SPATIAL] / s-strength[LUMA_SPATIAL];av_log(ctx, AV_LOG_VERBOSE, ls:%f cs:%f lt:%f ct:%f\n,s-strength[LUMA_SPATIAL], s-strength[CHROMA_SPATIAL],s-strength[LUMA_TMP], s-strength[CHROMA_TMP]);return 0;
}static av_cold void uninit(AVFilterContext *ctx)
{HQDN3DContext *s ctx-priv;av_freep(s-coefs[0]);av_freep(s-coefs[1]);av_freep(s-coefs[2]);av_freep(s-coefs[3]);av_freep(s-line[0]);av_freep(s-line[1]);av_freep(s-line[2]);av_freep(s-frame_prev[0]);av_freep(s-frame_prev[1]);av_freep(s-frame_prev[2]);
}static int query_formats(AVFilterContext *ctx)
{static const enum AVPixelFormat pix_fmts[] {AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV440P,AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,AV_PIX_FMT_YUV440P10,AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,AV_PIX_FMT_YUV440P12,AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,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 void calc_coefs(AVFilterContext *ctx)
{HQDN3DContext *s ctx-priv;for (int i 0; i 4; i)precalc_coefs(s-strength[i], s-depth, s-coefs[i]);
}static int config_input(AVFilterLink *inlink)
{AVFilterContext *ctx inlink-dst;HQDN3DContext *s inlink-dst-priv;const AVPixFmtDescriptor *desc av_pix_fmt_desc_get(inlink-format);int i, depth;uninit(inlink-dst);s-hsub desc-log2_chroma_w;s-vsub desc-log2_chroma_h;s-depth depth desc-comp[0].depth;for (i 0; i 3; i) {s-line[i] av_malloc_array(inlink-w, sizeof(*s-line[i]));if (!s-line[i])return AVERROR(ENOMEM);}for (i 0; i 4; i) {s-coefs[i] av_malloc((512LUT_BITS) * sizeof(int16_t));if (!s-coefs[i])return AVERROR(ENOMEM);}calc_coefs(ctx);if (ARCH_X86)ff_hqdn3d_init_x86(s);return 0;
}typedef struct ThreadData {AVFrame *in, *out;int direct;
} ThreadData;static int do_denoise(AVFilterContext *ctx, void *data, int job_nr, int n_jobs)
{HQDN3DContext *s ctx-priv;const ThreadData *td data;AVFrame *out td-out;AVFrame *in td-in;int direct td-direct;denoise(s, in-data[job_nr], out-data[job_nr],s-line[job_nr], s-frame_prev[job_nr],AV_CEIL_RSHIFT(in-width, (!!job_nr * s-hsub)),AV_CEIL_RSHIFT(in-height, (!!job_nr * s-vsub)),in-linesize[job_nr], out-linesize[job_nr],s-coefs[job_nr ? CHROMA_SPATIAL : LUMA_SPATIAL],s-coefs[job_nr ? CHROMA_TMP : LUMA_TMP]);return 0;
}static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{AVFilterContext *ctx inlink-dst;AVFilterLink *outlink ctx-outputs[0];AVFrame *out;int direct av_frame_is_writable(in) !ctx-is_disabled;ThreadData td;if (direct) {out in;} else {out ff_get_video_buffer(outlink, outlink-w, outlink-h);if (!out) {av_frame_free(in);return AVERROR(ENOMEM);}av_frame_copy_props(out, in);}td.in in;td.out out;td.direct direct;/* one thread per plane */ctx-internal-execute(ctx, do_denoise, td, NULL, 3);if (ctx-is_disabled) {av_frame_free(out);return ff_filter_frame(outlink, in);}if (!direct)av_frame_free(in);return ff_filter_frame(outlink, out);
}static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,char *res, int res_len, int flags)
{int ret;ret ff_filter_process_command(ctx, cmd, args, res, res_len, flags);if (ret 0)return ret;calc_coefs(ctx);return 0;
}#define OFFSET(x) offsetof(HQDN3DContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
static const AVOption hqdn3d_options[] {{ luma_spatial, spatial luma strength, OFFSET(strength[LUMA_SPATIAL]), AV_OPT_TYPE_DOUBLE, { .dbl 0.0 }, 0, DBL_MAX, FLAGS },{ chroma_spatial, spatial chroma strength, OFFSET(strength[CHROMA_SPATIAL]), AV_OPT_TYPE_DOUBLE, { .dbl 0.0 }, 0, DBL_MAX, FLAGS },{ luma_tmp, temporal luma strength, OFFSET(strength[LUMA_TMP]), AV_OPT_TYPE_DOUBLE, { .dbl 0.0 }, 0, DBL_MAX, FLAGS },{ chroma_tmp, temporal chroma strength, OFFSET(strength[CHROMA_TMP]), AV_OPT_TYPE_DOUBLE, { .dbl 0.0 }, 0, DBL_MAX, FLAGS },{ NULL }
};AVFILTER_DEFINE_CLASS(hqdn3d);static const AVFilterPad avfilter_vf_hqdn3d_inputs[] {{.name default,.type AVMEDIA_TYPE_VIDEO,.config_props config_input,.filter_frame filter_frame,},{ NULL }
};static const AVFilterPad avfilter_vf_hqdn3d_outputs[] {{.name default,.type AVMEDIA_TYPE_VIDEO},{ NULL }
};AVFilter ff_vf_hqdn3d {.name hqdn3d,.description NULL_IF_CONFIG_SMALL(Apply a High Quality 3D Denoiser.),.priv_size sizeof(HQDN3DContext),.priv_class hqdn3d_class,.init init,.uninit uninit,.query_formats query_formats,.inputs avfilter_vf_hqdn3d_inputs,.outputs avfilter_vf_hqdn3d_outputs,.flags AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,.process_command process_command,
};
