- 作者:老汪软件技巧
- 发表时间:2024-01-13 12:00
- 浏览量:
-go is a Go for the . It to into their Go , such as and audio and video files, media , and and . -go a and API, it for Go to the of .
本质上-go是对命令行工具的封装,最终功能的实现都是通过在go里执行命令行工具来实现。
我们来看个例子。
在go代码中调用命令行工具。
// 包装ffprobe工具
// Probe Run ffprobe on the specified file and return a JSON representation of the output.
func Probe(fileName string, kwargs ...KwArgs) (string, error) {
return ProbeWithTimeout(fileName, 0, MergeKwArgs(kwargs))
}
// 为命令行执行ffprobe增加timeout
func ProbeWithTimeout(fileName string, timeOut time.Duration, kwargs KwArgs) (string, error) {
args := KwArgs{
"show_format": "",
"show_streams": "",
"of": "json",
}
return ProbeWithTimeoutExec(fileName, timeOut, MergeKwArgs([]KwArgs{args, kwargs}))
}
// 生成ffprobe命令行执行用到的参数
func ProbeWithTimeoutExec(fileName string, timeOut time.Duration, kwargs KwArgs) (string, error) {
args := ConvertKwargsToCmdLineArgs(kwargs)
args = append(args, fileName)
ctx := context.Background()
// 将超时转换为context控制
if timeOut > 0 {
var cancel func()
ctx, cancel = context.WithTimeout(context.Background(), timeOut)
defer cancel()
}
cmd := exec.CommandContext(ctx, "ffprobe", args...)
buf := bytes.NewBuffer(nil)
stdErrBuf := bytes.NewBuffer(nil)
cmd.Stdout = buf
cmd.Stderr = stdErrBuf
for _, option := range GlobalCommandOptions {
option(cmd)
}
// 运行命令行的命令
// 实际运行的是: ffprobe -of json -show_format -show_streams ${fileName}
err := cmd.Run()
if err != nil {
return "", fmt.Errorf("[%s] %w", string(stdErrBuf.Bytes()), err)
}
return string(buf.Bytes()), nil
}
输出示例:
"streams": [
{
"index": 0,
"codec_name": "h264",
"codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
"profile": "Main",
"codec_type": "video",
"codec_tag_string": "avc1",
"codec_tag": "0x31637661",
"width": 320,
"height": 240,
"coded_width": 320,
"coded_height": 240,
"closed_captions": 0,
"film_grain": 0,
"has_b_frames": 0,
"sample_aspect_ratio": "1:1",
"display_aspect_ratio": "4:3",
"pix_fmt": "yuv420p",
"level": 13,
"chroma_location": "left",
"field_order": "progressive",
"refs": 1,
"is_avc": "true",
"nal_length_size": "4",
"id": "0x1",
"r_frame_rate": "30000/1001",
"avg_frame_rate": "30000/1001",
"time_base": "1/90000",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 627627,
"duration": "6.973633",
"bit_rate": "251413",
"bits_per_raw_sample": "8",
"nb_frames": "209",
"extradata_size": 37,
"disposition": {
"default": 1,
"dub": 0,
"original": 0,
"comment": 0,
"lyrics": 0,
"karaoke": 0,
"forced": 0,
"hearing_impaired": 0,
"visual_impaired": 0,
"clean_effects": 0,
"attached_pic": 0,
"timed_thumbnails": 0,
"captions": 0,
"descriptions": 0,
"metadata": 0,
"dependent": 0,
"still_image": 0
},
"tags": {
"language": "und",
"handler_name": "VideoHandler",
"vendor_id": "[0][0][0][0]"
}
},
{
"index": 1,
"codec_name": "aac",
"codec_long_name": "AAC (Advanced Audio Coding)",
"profile": "LC",
"codec_type": "audio",
"codec_tag_string": "mp4a",
"codec_tag": "0x6134706d",
"sample_fmt": "fltp",
"sample_rate": "44100",
"channels": 2,
"channel_layout": "stereo",
"bits_per_sample": 0,
"initial_padding": 0,
"id": "0x2",
"r_frame_rate": "0/0",
"avg_frame_rate": "0/0",
"time_base": "1/44100",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 310272,
"duration": "7.035646",
"bit_rate": "125587",
"nb_frames": "303",
"extradata_size": 2,
"disposition": {
"default": 1,
"dub": 0,
"original": 0,
"comment": 0,
"lyrics": 0,
"karaoke": 0,
"forced": 0,
"hearing_impaired": 0,
"visual_impaired": 0,
"clean_effects": 0,
"attached_pic": 0,
"timed_thumbnails": 0,
"captions": 0,
"descriptions": 0,
"metadata": 0,
"dependent": 0,
"still_image": 0
},
"tags": {
"language": "und",
"handler_name": "SoundHandler",
"vendor_id": "[0][0][0][0]"
}
}
],
"format": {
"filename": "./examples/sample_data/in1.mp4",
"nb_streams": 2,
"nb_programs": 0,
"format_name": "mov,mp4,m4a,3gp,3g2,mj2",
"format_long_name": "QuickTime / MOV",
"start_time": "0.000000",
"duration": "7.035646",
"size": "336833",
"bit_rate": "383001",
"probe_score": 100,
"tags": {
"major_brand": "isom",
"minor_version": "512",
"compatible_brands": "isomiso2avc1mp41",
"encoder": "Lavf57.71.100"
}
}
}