ffmpeg volumedetect滤镜获取音量

该博客介绍了如何通过ffmpeg库中的volumedetect滤镜来获取音频文件的音量信息。作者在C++代码中详细展示了如何初始化、配置和使用ffmpeg,包括读取输入文件、设置过滤器、处理音量数据以及输出到控制台的过程。代码实现了多个线程分别负责读取、音量检测和写入操作。尽管ffmpeg源码中没有直接提供获取音量的接口,但作者通过跟踪源码找到了在文件处理结束时触发音量打印的时机。

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ffmpeg中用volumedetect滤镜获取音量,结果是输出到控制台上,本人跟了一下ffmpeg源码,想尝试着看是否有具体的接口来获取音量大小,结果没有,在文件处理完之后,调用avfilter_graph_free时,会触发音量的控制台打印,如下所示:
在这里插入图片描述

代码结构如下:
在这里插入图片描述

其中FfmpegGetVolume.cpp的代码如下:

#include <iostream>
#include "VolumeGet.h"
#include <vector>

#ifdef	__cplusplus
extern "C"
{
#endif

#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avdevice.lib")
#pragma comment(lib, "avfilter.lib")
#pragma comment(lib, "postproc.lib")
#pragma comment(lib, "swresample.lib")
#pragma comment(lib, "swscale.lib")


#ifdef __cplusplus
};
#endif




int main()
{
	CVolumeGet cCVolumeGet;
	const char *pFileA = "E:\\learn\\ffmpeg\\FfmpegFilterTest\\x64\\Release\\huoluan3_audio.mp4";

	const char *pFileOut = "E:\\learn\\ffmpeg\\FfmpegFilterTest\\x64\\Release\\huoluan3_audio_copy.mp4";

	cCVolumeGet.StartVolumeGet(pFileA, pFileOut);
	cCVolumeGet.WaitFinish();

	return 0;
}



VolumeGet.h的代码如下:

#pragma once

#include <Windows.h>

#ifdef	__cplusplus
extern "C"
{
#endif
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libswresample/swresample.h"
#include "libavdevice/avdevice.h"
#include "libavutil/audio_fifo.h"
#include "libavutil/avutil.h"
#include "libavutil/fifo.h"
#include "libavutil/frame.h"
#include "libavutil/imgutils.h"

#include "libavfilter/avfilter.h"
#include "libavfilter/buffersink.h"
#include "libavfilter/buffersrc.h"


#ifdef __cplusplus
};
#endif

class CVolumeGet
{
public:
	CVolumeGet();
	~CVolumeGet();
public:
	int StartVolumeGet(const char *pFileA, const char *pFileOut);
	int WaitFinish();
private:
	int OpenFileA(const char *pFileA);
	int OpenOutPut(const char *pFileOut);
	int InitFilter(const char* filter_desc);
private:
	static DWORD WINAPI FileAReadProc(LPVOID lpParam);
	void FileARead();


	static DWORD WINAPI VolumeGetProc(LPVOID lpParam);
	void VolumeGet();

	static DWORD WINAPI AudioWriteProc(LPVOID lpParam);
	void AudioWrite();
private:
	AVFormatContext *m_pFormatCtx_FileA = NULL;

	AVCodecContext *m_pReadCodecCtx_AudioA = NULL;
	AVCodec *m_pReadCodec_AudioA = NULL;


	AVCodecContext	*m_pCodecEncodeCtx_Audio = NULL;
	AVFormatContext *m_pFormatCtx_Out = NULL;

	AVAudioFifo		*m_pAudioAFifo = NULL;
	AVAudioFifo		*m_pResampleFifo = NULL;
private:
	AVFilterGraph* m_pFilterGraph = NULL;
	AVFilterContext* m_pFilterCtxSrcAudioA = NULL;
	AVFilterContext* m_pFilterCtxSink = NULL;
private:
	CRITICAL_SECTION m_csAudioASection;
	CRITICAL_SECTION m_csResampleSection;
	HANDLE m_hFileAReadThread = NULL;
	HANDLE m_hVolumeGetThread = NULL;
	HANDLE m_hAudioWriteThread = NULL;

	AVRational m_streamTimeBase;
	SwrContext *m_pAudioConvertCtx = NULL;
};






VolumeGet.cpp的代码如下:


#include "VolumeGet.h"
//#include "log/log.h"





CVolumeGet::CVolumeGet()
{
	InitializeCriticalSection(&m_csAudioASection);
	InitializeCriticalSection(&m_csResampleSection);
}

CVolumeGet::~CVolumeGet()
{
	DeleteCriticalSection(&m_csAudioASection);
	DeleteCriticalSection(&m_csResampleSection);
}

int CVolumeGet::StartVolumeGet(const char *pFileA, const char *pFileOut)
{
	int ret = -1;
	do
	{
		ret = OpenFileA(pFileA);
		if (ret != 0)
		{
			break;
		}

		ret = OpenOutPut(pFileOut);
		if (ret != 0)
		{
			break;
		}

		char szFilterDesc[512] = { 0 };

		InitFilter(szFilterDesc);

		m_pAudioAFifo = av_audio_fifo_alloc((AVSampleFormat)m_pFormatCtx_FileA->streams[0]->codecpar->format,
			m_pFormatCtx_FileA->streams[0]->codecpar->channels, 3000 * 1024);

		m_pResampleFifo = av_audio_fifo_alloc((AVSampleFormat)m_pFormatCtx_FileA->streams[0]->codecpar->format,
			m_pFormatCtx_FileA->streams[0]->codecpar->channels, 3000 * 1024);

		int iSrcChLayout = m_pFormatCtx_FileA->streams[0]->codecpar->channel_layout;
		int iDstChLayout = m_pFormatCtx_Out->streams[0]->codecpar->channel_layout;

		int iSrcSampleRate = m_pFormatCtx_FileA->streams[0]->codecpar->sample_rate;
		int iDstSampleRate = m_pFormatCtx_Out->streams[0]->codecpar->sample_rate;

		int iSrcFmt = m_pFormatCtx_FileA->streams[0]->codecpar->format;
		int iDstFmt = m_pFormatCtx_Out->streams[0]->codecpar->format;

		m_pAudioConvertCtx = swr_alloc();
		av_opt_set_channel_layout(m_pAudioConvertCtx, "in_channel_layout", iSrcChLayout, 0);
		av_opt_set_channel_layout(m_pAudioConvertCtx, "out_channel_layout", iDstChLayout, 0);
		av_opt_set_int(m_pAudioConvertCtx, "in_sample_rate", iSrcSampleRate, 0);
		av_opt_set_int(m_pAudioConvertCtx, "out_sample_rate", iDstSampleRate, 0);
		av_opt_set_sample_fmt(m_pAudioConvertCtx, "in_sample_fmt", (AVSampleFormat)iSrcFmt, 0);
		av_opt_set_sample_fmt(m_pAudioConvertCtx, "out_sample_fmt", (AVSampleFormat)iDstFmt, 0);

		ret = swr_init(m_pAudioConvertCtx);
		

		m_hFileAReadThread = CreateThread(NULL, 0, FileAReadProc, this, 0, NULL);

		m_hVolumeGetThread = CreateThread(NULL, 0, VolumeGetProc, this, 0, NULL);

		m_hAudioWriteThread = CreateThread(NULL, 0, AudioWriteProc, this, 0, NULL);

	} while (0);

	return ret;
}

int CVolumeGet::WaitFinish()
{
	int ret = 0;
	do
	{
		if (NULL == m_hFileAReadThread)
		{
			break;
		}
		WaitForSingleObject(m_hFileAReadThread, INFINITE);

		CloseHandle(m_hFileAReadThread);
		m_hFileAReadThread = NULL;

		Sleep(1000);

		WaitForSingleObject(m_hVolumeGetThread, INFINITE);
		CloseHandle(m_hVolumeGetThread);
		m_hVolumeGetThread = NULL;


		WaitForSingleObject(m_hAudioWriteThread, INFINITE);
		CloseHandle(m_hAudioWriteThread);
		m_hAudioWriteThread = NULL;
	} while (0);

	return ret;
}

int CVolumeGet::OpenFileA(const char *pFileA)
{
	int ret = -1;

	do
	{
		if ((ret = avformat_open_input(&m_pFormatCtx_FileA, pFileA, 0, 0)) < 0) {
			printf("Could not open input file.");
			break;
		}
		if ((ret = avformat_find_stream_info(m_pFormatCtx_FileA, 0)) < 0) {
			printf("Failed to retrieve input stream information");
			break;
		}

		m_streamTimeBase = m_pFormatCtx_FileA->streams[0]->time_base;

		m_pReadCodec_AudioA = (AVCodec *)avcodec_find_decoder(m_pFormatCtx_FileA->streams[0]->codecpar->codec_id);

		m_pReadCodecCtx_AudioA = avcodec_alloc_context3(m_pReadCodec_AudioA);

		if (m_pReadCodecCtx_AudioA == NULL)
		{
			break;
		}
		avcodec_parameters_to_context(m_pReadCodecCtx_AudioA, m_pFormatCtx_FileA->streams[0]->codecpar);


		if (avcodec_open2(m_pReadCodecCtx_AudioA, m_pReadCodec_AudioA, NULL) < 0)
		{
			break;
		}

		ret = 0;
	} while (0);


	return ret;
}


int CVolumeGet::OpenOutPut(const char *pFileOut)
{
	int iRet = -1;

	AVStream *pAudioStream = NULL;

	do
	{
		avformat_alloc_output_context2(&m_pFormatCtx_Out, NULL, NULL, pFileOut);

		{
			AVCodec* pCodecEncode_Audio = (AVCodec *)avcodec_find_encoder(m_pFormatCtx_Out->oformat->audio_codec);

			m_pCodecEncodeCtx_Audio = avcodec_alloc_context3(pCodecEncode_Audio);
			if (!m_pCodecEncodeCtx_Audio)
			{
				break;
			}

			pAudioStream = avformat_new_stream(m_pFormatCtx_Out, pCodecEncode_Audio);
			if (!pAudioStream)
			{
				break;
			}


			m_pCodecEncodeCtx_Audio->sample_rate = m_pReadCodecCtx_AudioA->sample_rate;
			m_pCodecEncodeCtx_Audio->channel_layout = m_pReadCodecCtx_AudioA->channel_layout;
			m_pCodecEncodeCtx_Audio->channels = av_get_channel_layout_nb_channels(m_pCodecEncodeCtx_Audio->channel_layout);
			m_pCodecEncodeCtx_Audio->sample_fmt = (AVSampleFormat)m_pReadCodecCtx_AudioA->sample_fmt;


			if (m_pFormatCtx_Out->oformat->flags & AVFMT_GLOBALHEADER)
				m_pCodecEncodeCtx_Audio->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

			if (avcodec_open2(m_pCodecEncodeCtx_Audio, pCodecEncode_Audio, 0) < 0)
			{
				//编码器打开失败,退出程序
				break;
			}
		}

		if (!(m_pFormatCtx_Out->oformat->flags & AVFMT_NOFILE))
		{
			if (avio_open(&m_pFormatCtx_Out->pb, pFileOut, AVIO_FLAG_WRITE) < 0)
			{
				break;
			}
		}

		avcodec_parameters_from_context(pAudioStream->codecpar, m_pCodecEncodeCtx_Audio);

		if (avformat_write_header(m_pFormatCtx_Out, NULL) < 0)
		{
			break;
		}

		iRet = 0;
	} while (0);


	if (iRet != 0)
	{
		if (m_pCodecEncodeCtx_Audio != NULL)
		{
			avcodec_free_context(&m_pCodecEncodeCtx_Audio);
			m_pCodecEncodeCtx_Audio = NULL;
		}

		if (m_pFormatCtx_Out != NULL)
		{
			avformat_free_context(m_pFormatCtx_Out);
			m_pFormatCtx_Out = NULL;
		}
	}

	return iRet;
}


DWORD WINAPI CVolumeGet::FileAReadProc(LPVOID lpParam)
{
	CVolumeGet *pVolumeGet = (CVolumeGet *)lpParam;
	if (pVolumeGet != NULL)
	{
		pVolumeGet->FileARead();
	}
	return 0;
}

void CVolumeGet::FileARead()
{
	AVFrame *pFrame;
	pFrame = av_frame_alloc();

	int iReadedNbFrames = 0;
	AVPacket packet = { 0 };
	int ret = 0;
	while (1)
	{
		av_packet_unref(&packet);

		ret = av_read_frame(m_pFormatCtx_FileA, &packet);
		if (ret == AVERROR(EAGAIN))
		{
			continue;
		}
		else if (ret == AVERROR_EOF)
		{
			break;
		}
		else if (ret < 0)
		{
			break;
		}

		ret = avcodec_send_packet(m_pReadCodecCtx_AudioA, &packet);

		if (ret >= 0)
		{
			ret = avcodec_receive_frame(m_pReadCodecCtx_AudioA, pFrame);
			if (ret == AVERROR(EAGAIN))
			{
				continue;
			}
			else if (ret == AVERROR_EOF)
			{
				break;
			}
			else if (ret < 0) {
				break;
			}

			iReadedNbFrames += pFrame->nb_samples;

			while (1)
			{
				int buf_space = av_audio_fifo_space(m_pAudioAFifo);
				if (buf_space >= pFrame->nb_samples)
				{
					EnterCriticalSection(&m_csAudioASection);
					ret = av_audio_fifo_write(m_pAudioAFifo, (void **)pFrame->data, pFrame->nb_samples);
					LeaveCriticalSection(&m_csAudioASection);

					break;
				}
				else
				{
					Sleep(100);
				}
			}

		}


		if (ret == AVERROR(EAGAIN))
		{
			continue;
		}
	}

	av_frame_free(&pFrame);
}

DWORD WINAPI CVolumeGet::VolumeGetProc(LPVOID lpParam)
{
	CVolumeGet *pVolumeGet = (CVolumeGet *)lpParam;
	if (pVolumeGet != NULL)
	{
		pVolumeGet->VolumeGet();
	}
	return 0;
}


void CVolumeGet::VolumeGet()
{
	int ret = 0;



	AVFrame *pFrameAudioOut = av_frame_alloc();

	pFrameAudioOut->nb_samples = m_pFormatCtx_Out->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_Out->streams[0]->codecpar->frame_size : 1024;
	pFrameAudioOut->channel_layout = m_pFormatCtx_Out->streams[0]->codecpar->channel_layout;
	pFrameAudioOut->format = m_pFormatCtx_Out->streams[0]->codecpar->format;
	pFrameAudioOut->sample_rate = m_pFormatCtx_Out->streams[0]->codecpar->sample_rate;
	pFrameAudioOut->channels = m_pFormatCtx_Out->streams[0]->codecpar->channels;
	av_frame_get_buffer(pFrameAudioOut, 0);


	AVPacket packet = { 0 };

	int iWriteNbSamples = 0;

	while (1)
	{
		if (NULL == m_pAudioAFifo)
		{
			break;
		}
		AVFrame *pFrameAudioA = av_frame_alloc();

		pFrameAudioA->nb_samples = m_pFormatCtx_FileA->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_FileA->streams[0]->codecpar->frame_size : 1024;
		pFrameAudioA->channel_layout = m_pFormatCtx_FileA->streams[0]->codecpar->channel_layout;
		pFrameAudioA->format = m_pFormatCtx_FileA->streams[0]->codecpar->format;
		pFrameAudioA->sample_rate = m_pFormatCtx_FileA->streams[0]->codecpar->sample_rate;
		pFrameAudioA->channels = m_pFormatCtx_FileA->streams[0]->codecpar->channels;
		av_frame_get_buffer(pFrameAudioA, 0);

		if (av_audio_fifo_size(m_pAudioAFifo) >=
			(m_pFormatCtx_Out->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_Out->streams[0]->codecpar->frame_size : 1024))
		{
			EnterCriticalSection(&m_csAudioASection);
			int readcount = av_audio_fifo_read(m_pAudioAFifo, (void **)pFrameAudioA->data,
				(m_pFormatCtx_FileA->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_FileA->streams[0]->codecpar->frame_size : 1024));
			LeaveCriticalSection(&m_csAudioASection);

			ret = av_buffersrc_add_frame(m_pFilterCtxSrcAudioA, pFrameAudioA);
			if (ret < 0)
			{
				break;
			}

			while (1)
			{
				ret = av_buffersink_get_frame_flags(m_pFilterCtxSink, pFrameAudioOut, 0);
				if (ret < 0)
				{
					break;
				}
				while (1)
				{
					int buf_space = av_audio_fifo_space(m_pResampleFifo);
					if (buf_space >= pFrameAudioOut->nb_samples)
					{
						iWriteNbSamples += pFrameAudioOut->nb_samples;
						EnterCriticalSection(&m_csResampleSection);
						ret = av_audio_fifo_write(m_pResampleFifo, (void **)pFrameAudioOut->data, pFrameAudioOut->nb_samples);
						LeaveCriticalSection(&m_csResampleSection);
						break;
					}
					else
					{
						Sleep(100);
					}
				}
				
				
			}
			av_frame_free(&pFrameAudioA);
		}
		else
		{
			if (m_hFileAReadThread == NULL)
			{
				break;
			}
			Sleep(1);
		}
	}

	av_frame_free(&pFrameAudioOut);
}

DWORD WINAPI CVolumeGet::AudioWriteProc(LPVOID lpParam)
{
	CVolumeGet *pVolumeGet = (CVolumeGet *)lpParam;
	if (pVolumeGet != NULL)
	{
		pVolumeGet->AudioWrite();
	}
	return 0;
}

void CVolumeGet::AudioWrite()
{
	int ret = 0;

	AVFrame *pFrameAudioResample = av_frame_alloc();

	pFrameAudioResample->nb_samples = m_pFormatCtx_Out->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_Out->streams[0]->codecpar->frame_size : 1024;
	pFrameAudioResample->channel_layout = m_pFormatCtx_Out->streams[0]->codecpar->channel_layout;
	pFrameAudioResample->format = m_pFormatCtx_Out->streams[0]->codecpar->format;
	pFrameAudioResample->sample_rate = m_pFormatCtx_Out->streams[0]->codecpar->sample_rate;
	pFrameAudioResample->channels = m_pFormatCtx_Out->streams[0]->codecpar->channels;
	av_frame_get_buffer(pFrameAudioResample, 0);


	AVPacket packet = { 0 };

	int iAudioFrameIndex = 0;

	AVFrame *pFrameAudioOut = NULL;

	while (1)
	{
		if (NULL == m_pResampleFifo)
		{
			break;
		}
		if (av_audio_fifo_size(m_pResampleFifo) >=
			(m_pFormatCtx_Out->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_Out->streams[0]->codecpar->frame_size : 1024))
		{
			EnterCriticalSection(&m_csResampleSection);
			int readcount = av_audio_fifo_read(m_pResampleFifo, (void **)pFrameAudioResample->data,
				(m_pFormatCtx_FileA->streams[0]->codecpar->frame_size > 0 ? m_pFormatCtx_FileA->streams[0]->codecpar->frame_size : 1024));
			LeaveCriticalSection(&m_csResampleSection);


			int dst_nb_samples = av_rescale_rnd(pFrameAudioResample->nb_samples, m_pReadCodecCtx_AudioA->sample_rate, m_pCodecEncodeCtx_Audio->sample_rate, AVRounding(1));

			ret = avcodec_send_frame(m_pCodecEncodeCtx_Audio, pFrameAudioResample);
			if (ret == AVERROR(EAGAIN))
			{
				continue;
			}
			
			ret = avcodec_receive_packet(m_pCodecEncodeCtx_Audio, &packet);
			if (ret == AVERROR(EAGAIN))
			{
				continue;
			}

			packet.stream_index = 0;
			packet.pts = iAudioFrameIndex * m_pFormatCtx_Out->streams[0]->codecpar->frame_size;
			packet.dts = iAudioFrameIndex * m_pFormatCtx_Out->streams[0]->codecpar->frame_size;
			packet.duration = m_pFormatCtx_Out->streams[0]->codecpar->frame_size;

			av_write_frame(m_pFormatCtx_Out, &packet);

			iAudioFrameIndex++;
		}
		else
		{
			if (m_hVolumeGetThread == NULL)
			{
				break;
			}
			Sleep(1);
		}
	}

	av_write_trailer(m_pFormatCtx_Out);
	avio_close(m_pFormatCtx_Out->pb);

	av_frame_free(&pFrameAudioResample);

	avfilter_graph_free(&m_pFilterGraph);
}


int CVolumeGet::InitFilter(const char* filter_desc)
{
	int ret = 0;

	char args_audioA[512];
	const char* name_audioA = "in0";

	const char* name_volumeFilter = "volumeFilter";

	AVFilter* filter_src_audioA = (AVFilter *)avfilter_get_by_name("abuffer");
	AVFilter* filter_sink = (AVFilter *)avfilter_get_by_name("abuffersink");

	AVFilter *filter_volume_detect = (AVFilter *)avfilter_get_by_name("volumedetect");

	AVFilterInOut* filter_output_videoA = avfilter_inout_alloc();
	AVFilterInOut* filter_input = avfilter_inout_alloc();
	m_pFilterGraph = avfilter_graph_alloc();

	sprintf_s(args_audioA, sizeof(args_audioA), "time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=0x%I64x",
		m_pReadCodecCtx_AudioA->time_base.num,
		m_pReadCodecCtx_AudioA->time_base.den,
		m_pReadCodecCtx_AudioA->sample_rate,
		av_get_sample_fmt_name((AVSampleFormat)m_pReadCodecCtx_AudioA->sample_fmt),
		m_pReadCodecCtx_AudioA->channel_layout);

	do
	{
		ret = avfilter_graph_create_filter(&m_pFilterCtxSrcAudioA, filter_src_audioA, name_audioA, args_audioA, NULL, m_pFilterGraph);
		if (ret < 0)
		{
			break;
		}

		AVFilterContext *volumeFilter_ctx;
		ret = avfilter_graph_create_filter(&volumeFilter_ctx, filter_volume_detect, name_volumeFilter, filter_desc, NULL, m_pFilterGraph);
		if (ret < 0)
		{
			break;
		}

		ret = avfilter_graph_create_filter(&m_pFilterCtxSink, filter_sink, "out", NULL, NULL, m_pFilterGraph);
		if (ret < 0)
		{
			break;
		}

		ret = av_opt_set_bin(m_pFilterCtxSink, "sample_fmts", (uint8_t*)&m_pCodecEncodeCtx_Audio->sample_fmt, sizeof(m_pCodecEncodeCtx_Audio->sample_fmt), AV_OPT_SEARCH_CHILDREN);
		if (ret < 0)
		{
			break;
		}
		ret = av_opt_set_bin(m_pFilterCtxSink, "channel_layouts", (uint8_t*)&m_pCodecEncodeCtx_Audio->channel_layout, sizeof(m_pCodecEncodeCtx_Audio->channel_layout), AV_OPT_SEARCH_CHILDREN);
		if (ret < 0)
		{
			break;
		}
		ret = av_opt_set_bin(m_pFilterCtxSink, "sample_rates", (uint8_t*)&m_pCodecEncodeCtx_Audio->sample_rate, sizeof(m_pCodecEncodeCtx_Audio->sample_rate), AV_OPT_SEARCH_CHILDREN);
		if (ret < 0)
		{
			break;
		}



		ret = avfilter_link(m_pFilterCtxSrcAudioA, 0, volumeFilter_ctx, 0);
		if (ret != 0)
		{
			break;
		}

		ret = avfilter_link(volumeFilter_ctx, 0, m_pFilterCtxSink, 0);
		if (ret != 0)
		{
			break;
		}

		ret = avfilter_graph_config(m_pFilterGraph, NULL);
		if (ret < 0)
		{
			break;
		}

		ret = 0;

	} while (0);


	avfilter_inout_free(&filter_input);
	av_free(filter_src_audioA);

	char* temp = avfilter_graph_dump(m_pFilterGraph, NULL);

	return ret;
}


<think>好的,我现在需要帮助用户在Java中使用FFmpeg进行音频降噪。首先,我得回想一下FFmpeg的相关知识,特别是关于音频处理的部分。用户提到了引用中的几个资源,比如使用FFmpeg命令进行音视频处理,还有volumedetect滤镜,但降噪可能需要不同的滤镜。 首先,FFmpeg中常用的降噪滤镜是什么?我记得可能有afftdn或者arnndn这样的滤镜。比如,afftdn是基于FFT的降噪器,适用于消除背景噪音。用户需要的是如何在Java中调用这些滤镜,而不是直接使用命令行,但根据引用[4],用户可以通过拼接FFmpeg命令并执行它们来实现。所以关键点在于构建正确的命令,并通过Java执行。 接下来,我需要确认如何正确应用这些滤镜。例如,afftdn的参数可能有噪声抑制的强度设置。用户可能需要调整这些参数以达到最佳效果。此外,引用[5]提到volumedetect用于音量检测,但降噪需要不同的处理步骤。 然后,关于Java中的具体实现,用户需要使用ProcessBuilder来执行FFmpeg命令。引用[3]和[4]中的例子展示了如何通过Java调用FFmpeg命令,比如处理视频截图或者格式转换。同样的方法可以用于音频降噪,只需替换为相应的滤镜参数。 可能需要注意的地方包括正确设置输入输出文件路径,处理可能出现的错误,以及确保FFmpeg的可执行文件在系统路径中或者指定其路径。此外,用户可能需要根据实际情况调整降噪参数,例如降噪的强度或阈值。 最后,还需要考虑如何测试降噪效果,可能需要用户多次尝试不同的参数设置。同时,引用[1]提到使用FFmpegFrameGrabber和FFmpegFrameRecorder,但用户可能更倾向于直接使用命令行方式,如引用[4]中的方法,通过拼接命令字符串来执行。 总结步骤:1.确定正确的FFmpeg降噪滤镜和参数;2.构建对应的FFmpeg命令字符串;3.在Java中使用ProcessBuilder执行该命令;4.处理执行结果和可能的异常;5.测试和调整参数。</think>在Java中使用FFmpeg进行音频降噪处理,可以通过调用FFmpeg的`afftdn`(自适应FFT降噪)或`arnndn`(基于递归神经网络的降噪)滤镜实现。以下是具体实现步骤: ### 一、FFmpeg降噪命令构建 核心命令格式为: ``` ffmpeg -i 输入文件 -af "afftdn=nf=-20" 输出文件 ``` 其中`nf=-20`表示将噪声基底降低20dB,参数值需根据实际音频质量调整。若要使用深度学习降噪滤镜: ``` ffmpeg -i input.wav -af "arnndn=model=模型路径" output.wav ``` ### 二、Java执行代码实现 ```java import java.io.*; public class AudioDenoiser { public static void main(String[] args) { File input = new File("input.wav"); File output = new File("output.wav"); // 构建命令参数 String[] command = { "ffmpeg", "-i", input.getAbsolutePath(), "-af", "afftdn=nf=-20", output.getAbsolutePath() }; executeFFmpegCommand(command); } private static void executeFFmpegCommand(String[] command) { try { Process process = new ProcessBuilder(command) .redirectErrorStream(true) .start(); // 读取执行日志 BufferedReader reader = new BufferedReader( new InputStreamReader(process.getInputStream())); String line; while ((line = reader.readLine()) != null) { System.out.println("[FFmpeg] " + line); } int exitCode = process.waitFor(); System.out.println("执行完成,退出码:" + exitCode); } catch (IOException | InterruptedException e) { e.printStackTrace(); } } } ``` ### 三、关键参数说明 1. **afftdn滤镜参数** - `nf=-30`: 噪声基底(单位dB)默认-20 - `tn=1`: 瞬态噪声抑制强度(0-1) - 示例:`"afftdn=nf=-30:tn=0.8"` 2. **arnndn滤镜参数** - 需下载预训练模型(如`rnnoise-models-2020-07-01.tar.gz`) - 指定模型路径:`arnndn=model=/models/rnn.ffmat` ### 四、性能优化建议 1. 预处理音频:先执行`highpass=50`过滤低频杂音[^5] 2. 多阶段处理:结合`compand`动态范围压缩提升效果 3. 并行处理:添加`-threads 4`参数启用多线程加速
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