比较好用媒体信息获取工具ffprobe

    之前在项目中一直用mediainfo来获取媒体文件或流的信息，比如封装格式、音视频编码格式、码率等信息。

    但实际使用中发现mediainfo输出的字段不容易被解析，而且表述方法不统一。例如，对于h264这种编码格式，mediainfo可能输出的表述为H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10；还比如，对于mp3这样的音频格式，居然会分两个字段进行描述，分别说明mpeg和layer3。所以在项目中苦于这种不确定的因素。

    之前就在ffmpeg官网上看过ffprobe，不过名气被ffmpeg盖过了，没多少人使用，网上也没有什么介绍的资料。算了，自己写一点，记录一下吧。

官网说明：http://ffmpeg.org/ffprobe.html

ffprobe的编译就不说了，编译ffmpeg时控制一下configure的参数即可。

OK，下面简单使用一下。

命令行：

./ffprobe -print_format json -show_format -show_streams -i ./video/c.ts

其中：  

-print_format json（以json格式输出）， 

-show_format（输出封装格式信息），

-show_streams（输出流信息），

-i ./video/c.ts（输入文件）

Input #0, mpegts, from './video/c.ts':
  Duration: 00:00:59.67, start: 1.172511, bitrate: 919 kb/s
  Program 1 
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 640x360, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x101]: Audio: aac ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 103 kb/s
    "streams": [
        {
            "index": 0,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
            "profile": "High",
            "codec_type": "video",
            "codec_time_base": "1/50",
            "codec_tag_string": "[27][0][0][0]",
            "codec_tag": "0x001b",
            "width": 640,
            "height": 360,
            "has_b_frames": 2,
            "sample_aspect_ratio": "0:1",
            "display_aspect_ratio": "0:1",
            "pix_fmt": "yuv420p",
            "level": 30,
            "is_avc": "0",
            "nal_length_size": "0",
            "id": "0x100",
            "r_frame_rate": "25/1",
            "avg_frame_rate": "25/1",
            "time_base": "1/90000",
            "start_pts": 108000,
            "start_time": "1.200000",
            "duration_ts": 5367600,
            "duration": "59.640000",
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0
            }
        },
        {
            "index": 1,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "codec_type": "audio",
            "codec_time_base": "1/44100",
            "codec_tag_string": "[15][0][0][0]",
            "codec_tag": "0x000f",
            "sample_fmt": "fltp",
            "sample_rate": "44100",
            "channels": 2,
            "bits_per_sample": 0,
            "id": "0x101",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/90000",
            "start_pts": 105526,
            "start_time": "1.172511",
            "duration_ts": 5340780,
            "duration": "59.342000",
            "bit_rate": "103359",
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0
            }
        }
    ],
    "format": {
        "filename": "./video/c.ts",
        "nb_streams": 2,
        "format_name": "mpegts",
        "format_long_name": "MPEG-TS (MPEG-2 Transport Stream)",
        "start_time": "1.172511",
        "duration": "59.667489",
        "size": "6859932",
        "bit_rate": "919754"
    }
}

嗯，效果还是不错的。