视频转码用例

206 次浏览 2026年 5月 20日下午3:36

## 简介
NMSv3.12及之后版本支持调用ffmpeg进行实时视频转码，应用场景为
- 1转高清转多路中低分辨率、码率
- h264、h265 互转
- 实时添加图片，文字等滤镜

## 注意事项
- 转码模板目前只支持服务启动前预设好，服务启动后不能修改
- 转码必然消耗大量cpu性能，请合理设置转码任务，避免影响正常的视频直播功能
- 在各个系统上，ffmpeg支持硬件加速的编解码，可以的话尽量使用，但也需注意硬件加速的最大处理能力
- 添加文字，图片水印一样需要对原视频解码后再编码

## 高清转多路低清
用于1路高清推流，如1080，转为多路低分辨率低码率，以帮助低带宽用户流畅播放
config.ini文件，打开注释
```
; ffmpeg路径
ffmpeg_binpath = /usr/local/bin/ffmpeg
; ffmpeg日志等级
ffmpeg_loglevel = 16
; 实时多分辨率转码模板文件路径, json格式, 注释则关闭
fission_template = ./fission.json
```
安装ffmpeg可执行程序到/usr/local/bin/ffmpeg或指定其他路径
编辑fission.json转码模板文件
```
[
    {
        "rule": "live/*",
        "###_rule": "匹配规则的流进行实时转码",
        "hwaccel": "",
        "###_hwaccel": "使用硬件加速解码,可选 videotoolbox, vaapi, dxva2, nvdec, vdpau等",
        "model": [
            {
                "name": "720",
                "###_name": "name作为标识区分,加入到流的后缀,使用字母或数字. 如原流为/live/demo,则拼接上/live/demo_720",
                "video": {
                    "filter": "",
                    "code": "libx264",
                    "###_code": "编码器可选,libx264,libx265,*_nvenc,*_amf,*_qsv,*_mf,*_vaapi,*_videotoolbox等.也可设置为copy则不转码.也可设置为none.注意当进行265视频转码时,需要ffmpeg打flv_h265_id=12 的补丁",
                    "profile": "main",
                    "preset": "veryfast",
                    "tune": "zerolatency",
                    "bitrate": 1200000,
                    "width": 1280,
                    "height": 720,
                    "framerate": 24,
                    "keyint": 2
                },
                "audio": {
                    "filter": "",
                    "code": "aac",
                    "bitrate": 64000,
                    "samplerate": 44100,
                    "channels": 2
                }
            },
            {
                "name": "360",
                "video": {
                    "filter": "",
                    "code": "libx264",
                    "profile": "baseline",
                    "preset": "superfast",
                    "tune": "zerolatency",
                    "bitrate": 500000,
                    "width": 640,
                    "height": 360,
                    "framerate": 20,
                    "keyint": 2
                },
                "audio": {
                    "filter": "",
                    "code": "aac",
                    "bitrate": 48000,
                    "samplerate": 44100,
                    "channels": 1
                }
            }
        ]
    }
]
```
默认配置就是对/live/* 的流进行转码，转出720和360两个分辨率，新的流名称在原流名称后添加_720和_360，码率更低。
![](https://www.nodemedia.cn/doc/server/../Public/Uploads/2022-03-20/62371dccbc024.png)

##  h265 转 h264
这种场景用于h265监控摄像头推流后转为兼容性更高的 h264流
```
[
    {
        "rule": "live/*",
        "###_rule": "匹配规则的流进行实时转码",
        "hwaccel": "",
        "###_hwaccel": "使用硬件加速解码,可选 videotoolbox, vaapi, dxva2, nvdec, vdpau等",
        "model": [
            {
                "name": "264",
                "###_name": "name作为标识区分,加入到流的后缀,使用字母或数字. 如原流为/live/demo,则拼接上/live/demo_264",
                "video": {
                    "filter": "",
                    "code": "libx264",
                    "###_code": "编码器可选,libx264,libx265,*_nvenc,*_amf,*_qsv,*_mf,*_vaapi,*_videotoolbox等.也可设置为copy则不转码.也可设置为none.注意当进行265视频转码时,需要ffmpeg打flv_h265_id=12 的补丁",
                    "profile": "main",
                    "preset": "veryfast",
                    "tune": "zerolatency",
                    "bitrate": 1200000,
                    "width": 1920,
                    "height": 1080,
                    "framerate": 25,
                    "keyint": 3
                },
                "audio": {
                    "filter": "",
                    "code": "aac",
                    "bitrate": 64000,
                    "samplerate": 44100,
                    "channels": 2
                }
            }
        ]
    }
]
```

## 实时添加文字滤镜
```
[
    {
        "rule": "live/*",
        "###_rule": "匹配规则的流进行实时转码",
        "hwaccel": "",
        "###_hwaccel": "使用硬件加速解码,可选 videotoolbox, vaapi, dxva2, nvdec, vdpau等",
        "model": [
            {
                "name": "logo",
                "###_name": "name作为标识区分,加入到流的后缀,使用字母或数字. 如原流为/live/demo,则拼接上/live/demo_logo",
                "video": {
                    "filter": "drawtext=fontfile=simhei.ttf:text=这是文字水印:x=20:y=20:fontsize=48:fontcolor=white:shadowy=2",
                    "code": "libx264",
                    "###_code": "编码器可选,libx264,libx265,*_nvenc,*_amf,*_qsv,*_mf,*_vaapi,*_videotoolbox等.也可设置为copy则不转码.也可设置为none.注意当进行265视频转码时,需要ffmpeg打flv_h265_id=12 的补丁",
                    "profile": "main",
                    "preset": "veryfast",
                    "tune": "zerolatency",
                    "bitrate": 800000,
                    "width": 854,
                    "height": 480,
                    "framerate": 30,
                    "keyint": 3
                },
                "audio": {
                    "filter": "",
                    "code": "aac",
                    "bitrate": 64000,
                    "samplerate": 44100,
                    "channels": 2
                }
            }
        ]
    }
]
```
如果提示错误 
[Parsed_drawtext_0 @ 0x7f8202a12c40] Could not load font "simhei.ttf": cannot open resource
是因为ffmpeg未找到字体文件，可指定字体的绝对路径或将simhei.ttf拷贝到nms目录下
字体不限
![](https://www.nodemedia.cn/doc/server/../Public/Uploads/2022-03-21/6237cb06e0522.png)
## 实时添加图片滤镜
将logo.png文件拷贝到nms程序目录下
```
[
    {
        "rule": "live/*",
        "###_rule": "匹配规则的流进行实时转码",
        "hwaccel": "",
        "###_hwaccel": "使用硬件加速解码,可选 videotoolbox, vaapi, dxva2, nvdec, vdpau等",
        "model": [
            {
                "name": "logo",
                "###_name": "name作为标识区分,加入到流的后缀,使用字母或数字. 如原流为/live/demo,则拼接上/live/demo_logo",
                "video": {
                    "filter": "movie=logo.png[watermark];[in][watermark] overlay=main_w-overlay_w-10:10[out]",
                    "code": "libx264",
                    "###_code": "编码器可选,libx264,libx265,*_nvenc,*_amf,*_qsv,*_mf,*_vaapi,*_videotoolbox等.也可设置为copy则不转码.也可设置为none.注意当进行265视频转码时,需要ffmpeg打flv_h265_id=12 的补丁",
                    "profile": "main",
                    "preset": "veryfast",
                    "tune": "zerolatency",
                    "bitrate": 800000,
                    "width": 854,
                    "height": 480,
                    "framerate": 30,
                    "keyint": 3
                },
                "audio": {
                    "filter": "",
                    "code": "aac",
                    "bitrate": 64000,
                    "samplerate": 44100,
                    "channels": 2
                }
            }
        ]
    }
]
```
则在视频右上角添加了一个透明图片水印
![](https://www.nodemedia.cn/doc/server/../Public/Uploads/2022-03-21/6237cba784ee4.png)

### 左上
```
overlay=10:10
```
### 右上
```
overlay=main_w-overlay_w-10:10
```
### 左下
```
overlay=10:main_h-overlay_h-10
```
### 右下
```
overlay=main_w-overlay_w-10:main_h-overlay_h-10
```

文档

视频转码用例