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I'm using ffprobe to analyze media files stored on a remote server. This seems to work well, but for some files the duration is missing or incorrect (usually longer than it should be). Other times it returns this information accurately, and it doesn't seem to be related to the media type (codec, etc.).

Here's an example of a command that works:

ffprobe -v quiet -print_format json -show_streams -show_format http://host.com/file.aiff

{
"streams": [
    {
        "index": 0,
        "codec_name": "pcm_s16be",
        "codec_long_name": "PCM signed 16-bit big-endian",
        "codec_type": "audio",
        "codec_time_base": "1/44100",
        "codec_tag_string": "[0][0][0][0]",
        "codec_tag": "0x0000",
        "sample_fmt": "s16",
        "sample_rate": "44100",
        "channels": 2,
        "bits_per_sample": 16,
        "r_frame_rate": "0/0",
        "avg_frame_rate": "0/0",
        "time_base": "1/44100",
        "start_pts": 0,
        "start_time": "0.000000",
        "duration_ts": 8494248,
        "duration": "192.613333",
        "bit_rate": "1411200",
        "nb_frames": "8494248",
        "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": "http://host.com/file.aiff",
    "nb_streams": 1,
    "nb_programs": 0,
    "format_name": "aiff",
    "format_long_name": "Audio IFF",
    "start_time": "0.000000",
    "duration": "192.613333",
    "probe_score": 100
}
}

Here's an example of one that doesn't:

ffprobe -v quiet -print_format json -show_streams -show_format "http://host.com/file.wav"

Which generates this result:

{
"streams": [
    {
        "index": 0,
        "codec_name": "pcm_s16le",
        "codec_long_name": "PCM signed 16-bit little-endian",
        "codec_type": "audio",
        "codec_time_base": "1/44100",
        "codec_tag_string": "[1][0][0][0]",
        "codec_tag": "0x0001",
        "sample_fmt": "s16",
        "sample_rate": "44100",
        "channels": 2,
        "bits_per_sample": 16,
        "r_frame_rate": "0/0",
        "avg_frame_rate": "0/0",
        "time_base": "1/44100",
        "bit_rate": "1411200",
        "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": "http://host.com/file.wav",
    "nb_streams": 1,
    "nb_programs": 0,
    "format_name": "wav",
    "format_long_name": "WAV / WAVE (Waveform Audio)",
    "bit_rate": "1411200",
    "probe_score": 99
}
}

These two examples are different formats, but I've seen it work and not work when the format is the same, I just don't have an example handy.

What I'd like to know is if there is something I can change about the parameters I'm using with ffprobe to allow the duration to be determined consistently and accurate, or any information I can find as to how ffprobe works so I figure out how I might change the input files, etc. so they work correctly.

Alternatively, if there is a different tool that works more reliably (it would need to be an open-source Linux tool) any suggestions or recommendations are welcome.

4

2 回答 2

5

一种简单的解决方案是使用 -show_packets 选项

ffprobe -i input.mp4 -show_packets > a.txt

现在打开 a.txt 并转到最后一个数据包并查看 dts_time 值，这将是文件的准确持续时间。如果未定义 dts_time，请检查 pts_time 值。

于 2015-10-26T13:07:36.157 回答
3

元数据可能不正确。最正确的方法是解码整个文件：

$ ffmpeg -i input.webm -f null -
...
frame=206723 fps=1390 q=-0.0 Lsize=N/A time=00:57:28.87 bitrate=N/A speed=23.2x

来源：https ://trac.ffmpeg.org/wiki/FFprobeTips#Getdurationbydecoding

于 2019-01-10T15:25:10.440 回答