视频信息查看，帧信息查看

1、查看视频流index的方法：  

方法一、ffprobe /Users/laa/Desktop/abc/视频.mp4

ffprobe -select_streams 0 -show_packets /Users/laa/Desktop/abc/shipin.mp4 |grep flags=

方法二、通过-show_streams参数可以查看到多媒体文件中的流信息，流的信息使用STREAMS标签括起来，可以看到

index=0
codec_name=h264

输入命令：ffprobe -show_streams /Users/lily/Desktop/白雾/只有一个关键帧.mp4
输出如下：
ffprobe version 3.4.2 Copyright (c) 2007-2018 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/liaa/Desktop/abc/只有一个关键帧.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.25.100
    comment         : GIFSHOW [26196011][iOS][10.3.3][iPhone7,1][5.2.0.222][Camera:b]
  Duration: 00:00:11.54, start: 0.000000, bitrate: 927 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x960, 858 kb/s, 19.49 fps, 20 tbr, 19200 tbn, 1200 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[STREAM]
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=197/7680
codec_tag_string=avc1
codec_tag=0x31637661
width=720
height=960
coded_width=720
coded_height=960
has_b_frames=2
sample_aspect_ratio=0:1
display_aspect_ratio=0:1
pix_fmt=yuv420p
level=52
color_range=unknown
color_space=unknown
color_transfer=unknown
color_primaries=unknown
chroma_location=left
field_order=unknown
timecode=N/A
refs=1
is_avc=true
nal_length_size=4
id=N/A
r_frame_rate=20/1
avg_frame_rate=3840/197
time_base=1/19200
start_pts=0
start_time=0.000000
duration_ts=221626
duration=11.543021
bit_rate=858673
max_bit_rate=N/A
bits_per_raw_sample=8
nb_frames=225
nb_read_frames=N/A
nb_read_packets=N/A
DISPOSITION:default=1
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0
TAG:language=und
TAG:handler_name=VideoHandler
[/STREAM]
[STREAM]
index=1
codec_name=aac
codec_long_name=AAC (Advanced Audio Coding)
profile=LC
codec_type=audio
codec_time_base=1/44100
codec_tag_string=mp4a
codec_tag=0x6134706d
sample_fmt=fltp
sample_rate=44100
channels=1
channel_layout=mono
bits_per_sample=0
id=N/A
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/44100
start_pts=0
start_time=0.000000
duration_ts=503931
duration=11.427007
bit_rate=63471
max_bit_rate=63471
bits_per_raw_sample=N/A
nb_frames=493
nb_read_frames=N/A
nb_read_packets=N/A
DISPOSITION:default=1
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0
TAG:language=und
TAG:handler_name=SoundHandler
[/STREAM]

2.使用

ffprobe -select_streams 0 -show_packets，查看关键帧数量，最后一行的就是：
其中，

-select_streams 后面跟视频的index，上个命令可以看到。

ffprobe -select_streams 0 -show_packets /Users/laa/Desktop/abc/只有一个关键帧.mp4 |grep flags=K |wc -l

ffprobe version 3.4.2 Copyright (c) 2007-2018 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/laa/Desktop/abc/只有一个关键帧.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.25.100
    comment         : GIFSHOW [26196011][iOS][10.3.3][iPhone7,1][5.2.0.222][Camera:b]
  Duration: 00:00:11.54, start: 0.000000, bitrate: 927 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 720x960, 858 kb/s, 19.49 fps, 20 tbr, 19200 tbn, 1200 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
       1