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• FFMPEG nb_frames vs nb_read_frames

  10 août 2022, par Alex Willcox

  I have videos captured at 200fps and I'm trying to label each frame with it's frame number. However, looking at the original videos with the following command :

  


  ffprobe.exe -i YR7-020320-B1-2.avi -print_format json -loglevel fatal -show_streams -count_frames -select_streams v


  


  and I get the following output :

  


  {
    "streams": [
        {
            "index": 0,
            "codec_name": "dvvideo",
            "codec_long_name": "DV (Digital Video)",
            "codec_type": "video",
            "codec_time_base": "1001/30000",
            "codec_tag_string": "dvsd",
            "codec_tag": "0x64737664",
            "width": 720,
            "height": 480,
            "coded_width": 720,
            "coded_height": 480,
            "closed_captions": 0,
            "has_b_frames": 0,
            "sample_aspect_ratio": "8:9",
            "display_aspect_ratio": "4:3",
            "pix_fmt": "yuv411p",
            "level": -99,
            "chroma_location": "topleft",
            "refs": 1,
            "r_frame_rate": "30000/1001",
            "avg_frame_rate": "200/1",
            "time_base": "1/200",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 67735,
            "duration": "338.675000",
            "bit_rate": "192003405",
            "nb_frames": "67735",
            "nb_read_frames": "55652",
            "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,
                "timed_thumbnails": 0
            }
        }
    ]
}


  


  I was wondering what the difference between nb_frames and nb-read-frames is, to know which one denotes the real total number of frames.

  


  Thanks !

  


• Edit H264 video stream header information ("start_pts" and "start_time")

  27 juin 2020, par David

  I have a video clip that appears to be slightly corrupted. Does not play on VLC but works on Potplayer. I used FFprobe to get information on the video.

  


  The problem appears to be with the start points of the video stream :

  


  time_base=1/90000
start_pts=585050940
start_time=6500.566000
duration_ts=585050940
duration=6500.566000
bit_rate=3123218


  


  I'm just wondering whether it is possible to manually edit the "start_pts" and "start_time" to 0 ? Is there any specific software to do this ? Due to large size of video file, I couldn't load it in Notepad++.

  


  Full ffprobe output shown below :

  


  # ffprobe output

[streams.stream.0]
index=0
codec_name=h264
codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
profile=unknown
codec_type=video
codec_time_base=1/60
codec_tag_string=avc1
codec_tag=0x31637661
width=1920
height=1080
coded_width=1920
coded_height=1080
closed_captions=0
has_b_frames=0
sample_aspect_ratio=N/A
display_aspect_ratio=N/A
pix_fmt=unknown
level=-99
color_range=unknown
color_space=unknown
color_transfer=unknown
color_primaries=unknown
chroma_location=unspecified
field_order=unknown
timecode=N/A
refs=1
is_avc=true
nal_length_size=4
id=N/A
r_frame_rate=30/1
avg_frame_rate=30/1
time_base=1/90000
start_pts=585050940
start_time=6500.566000
duration_ts=585050940
duration=6500.566000
bit_rate=3123218
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=195017
nb_read_frames=N/A
nb_read_packets=N/A

[streams.stream.0.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

[streams.stream.0.tags]
language=und
handler_name=VideoHandler

[streams.stream.1]
index=1
codec_name=aac
codec_long_name=AAC (Advanced Audio Coding)
profile=LC
codec_type=audio
codec_time_base=1/48000
codec_tag_string=mp4a
codec_tag=0x6134706d
sample_fmt=fltp
sample_rate=48000
channels=2
channel_layout=stereo
bits_per_sample=0
id=N/A
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/48000
start_pts=0
start_time=0.000000
duration_ts=312029184
duration=6500.608000
bit_rate=189376
max_bit_rate=189376
bits_per_raw_sample=N/A
nb_frames=304718
nb_read_frames=N/A
nb_read_packets=N/A

[streams.stream.1.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

[streams.stream.1.tags]
language=eng
handler_name=SoundHandler

[format]
filename=D\:\\Start\\test.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=6500.608000
size=2703218140
bit_rate=3326726
probe_score=100

[format.tags]
major_brand=isom
minor_version=512
compatible_brands=isomiso2avc1mp41


  


• Solved : ffmpeg : How can a MOV with transparent background be created ?

  25 mars 2017, par Mat

  (Remark : the error sat, as usual, between back-rest and keyboard. Thanks, Mulvya !)

  Hi, specialists !

  I’m trying - with no success at all - to convert the green pixels of a background into transparent ones and output the result as clip with ffmpeg. N.b. I do not want to lay the clip over anything ; I’m not having a problem with that. What I want is a clip with transparent background for the OpenShot video editor (the chromakey filter of which doesn’t work satisfyingly).

  What I have tried (amongst a felt 1 zillion other things over the last 15 hrs.) was

  ffmpeg.exe -i in.mov -vf chromakey=0x008001:0.115:0.0 -c:v qtrle out.mov

  but the pixels simply would not be transparent. Seemingly, nothing happens. I reckon the filter is ok, because it works fine in a complex chain (overlaying a background image).

  The output of ffprompt -show_stream -show_format of out.mov is as follows :

  [STREAM]
  
  index=0
  
  codec_name=qtrle
  
  codec_long_name=QuickTime Animation (RLE) video
  
  profile=unknown
  
  codec_type=video
  
  codec_time_base=1/30
  
  codec_tag_string=rle
  
  codec_tag=0x20656c72
  
  width=1920
  
  height=1080
  
  coded_width=1920
  
  coded_height=1080
  
  has_b_frames=0
  
  sample_aspect_ratio=1:1
  
  display_aspect_ratio=16:9
  
  pix_fmt=bgra
  
  level=-99
  
  color_range=N/A
  
  color_space=unknown
  
  color_transfer=unknown
  
  color_primaries=unknown
  
  chroma_location=unspecified
  
  field_order=progressive
  
  timecode=N/A
  
  refs=1
  
  id=N/A
  
  r_frame_rate=30/1
  
  avg_frame_rate=30/1
  
  time_base=1/15360
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=54789
  
  duration=3.566992
  
  bit_rate=822383192
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=N/A
  
  nb_frames=107
  
  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=eng
  
  TAG:handler_name=DataHandler
  
  TAG:encoder=Lavc57.64.101 qtrle
  
  [/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=2
  
  channel_layout=stereo
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/44100
  
  start_pts=926
  
  start_time=0.020998
  
  duration_ts=157481
  
  duration=3.570998
  
  bit_rate=132103
  
  max_bit_rate=132103
  
  bits_per_raw_sample=N/A
  
  nb_frames=153
  
  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=eng
  
  TAG:handler_name=DataHandler
  
  [/STREAM]
  
  [FORMAT]
  
  filename=out.mov
  
  nb_streams=2
  
  nb_programs=0
  
  format_name=mov,mp4,m4a,3gp,3g2,mj2
  
  format_long_name=QuickTime / MOV
  
  start_time=0.000000
  
  duration=3.567000
  
  size=366708874
  
  bit_rate=822447712
  
  probe_score=100
  
  TAG:major_brand=qt
  
  TAG:minor_version=512
  
  TAG:compatible_brands=qt
  
  TAG:encoder=Lavf57.56.101
  
  [/FORMAT]

  I have a "sample" clip which shows the behaviour I want, with the following stream and information :

  [STREAM]
  
  index=0
  
  codec_name=qtrle
  
  codec_long_name=QuickTime Animation (RLE) video
  
  profile=unknown
  
  codec_type=video
  
  codec_time_base=1/24
  
  codec_tag_string=rle
  
  codec_tag=0x20656c72
  
  width=1920
  
  height=1080
  
  coded_width=1920
  
  coded_height=1080
  
  has_b_frames=0
  
  sample_aspect_ratio=0:1
  
  display_aspect_ratio=0:1
  
  pix_fmt=bgra
  
  level=-99
  
  color_range=N/A
  
  color_space=unknown
  
  color_transfer=unknown
  
  color_primaries=unknown
  
  chroma_location=unspecified
  
  field_order=progressive
  
  timecode=N/A
  
  refs=1
  
  id=N/A
  
  r_frame_rate=24/1
  
  avg_frame_rate=24/1
  
  time_base=1/12288
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=74760
  
  duration=6.083984
  
  bit_rate=49226848
  
  max_bit_rate=N/A
  
  bits_per_raw_sample=N/A
  
  nb_frames=146
  
  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=eng
  
  TAG:handler_name=DataHandler
  
  TAG:encoder=Lavc57.24.102 qtrle
  
  [/STREAM]
  
  [STREAM]
  
  index=1
  
  codec_name=aac
  
  codec_long_name=AAC (Advanced Audio Coding)
  
  profile=LC
  
  codec_type=audio
  
  codec_time_base=1/48000
  
  codec_tag_string=mp4a
  
  codec_tag=0x6134706d
  
  sample_fmt=fltp
  
  sample_rate=48000
  
  channels=2
  
  channel_layout=stereo
  
  bits_per_sample=0
  
  id=N/A
  
  r_frame_rate=0/0
  
  avg_frame_rate=0/0
  
  time_base=1/48000
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=293856
  
  duration=6.122000
  
  bit_rate=53537
  
  max_bit_rate=128000
  
  bits_per_raw_sample=N/A
  
  nb_frames=288
  
  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=eng
  
  TAG:handler_name=DataHandler
  
  [/STREAM]
  
  [FORMAT]
  
  filename=templateOK.mov
  
  nb_streams=2
  
  nb_programs=0
  
  format_name=mov,mp4,m4a,3gp,3g2,mj2
  
  format_long_name=QuickTime / MOV
  
  start_time=0.000000
  
  duration=6.144000
  
  size=37478506
  
  bit_rate=48800138
  
  probe_score=100
  
  TAG:major_brand=qt
  
  TAG:minor_version=512
  
  TAG:compatible_brands=qt
  
  TAG:encoder=Lavf57.25.100
  
  [/FORMAT]

  and I simply am not able to spot the relevant difference.

  Any suggestions would be highly appreciated !

  Cheers,

  Mat

  The input, output and the working template can be found here.

  (The security issue you might see when clicking the link comes from the server certificate being self-signed. You can accept a temporal exception. Btw : The ridiculous file size of the output file will be the next nut to crack. Probably s.t. about compression.)