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• What is ffprobe metadata "programs" ?

  27 août 2020, par nonayme

  All in the topic : what are "progams" in context of video ?

  


  As you may expect, any google lookup containg "programs" yield many irrelevant results... no matter search tricks you can apply.

  


  I tried some general search about video metadata, found a glossary about digital & multimedia, and also a search engine about metadata but didnt get anything.

  


  In the ffprobe doc it seems to be sort of the container, but what is its use ?

  


  thanks for any reply which lift this fog ^^

  


• OBS and OBS Portable Recording Into Same File Simultaneously

  26 juin 2020, par aerodavo

  Corrupted video file, FFprobe output text file, and FFmpeg output text files are all available to download here :
https://drive.google.com/drive/folders/1R0Y5plgkhTWWFNNKgSNJ5yitpKQbIKgg?usp=sharing

  


  I'm hoping there is a way to extract good video and audio from this video file, this was for a very important job that is impossible to do again. The video linked is a 1 minute recreation of the exact same problem... the actual video file is confidential (for a legal court case) and is much longer/larger. I used the exact same settings, the only difference was the window OBS was capturing (I used a YouTube video as opposed to the videoconference software window used for the deposition).

  


  Here's what happened :

  


  In OBS and OBS Portable, I had the save location set to the same exact folder (this was not how I intended it to be, but I made a last minute change to accommodate what I suspected was a faulty hard drive). I also had a hotkey to start recording on both apps simultaneously. I left the auto-naming scheme in place for both instances of OBS since they were supposed to be saving to two totally different external hard drives. I have since changed the auto-naming so it won't happen again, but this perfect storm resulted in both recordings being written into a single file (see link above), instead of two files as intended. It is unplayabe in VLC.

  


  I ran an FFprobe (available via link above), and found that there are 8 streams in the file. Each file should have had 4 streams (1 video and 3 audio streams per my setup in OBS), so at first glance it looks like all the data is there in some form/arrangement.

  


  I tried to map the 0:0 stream to a new file and tried the same thing with the 0:4 stream (these are the video streams), but did not have any luck extracting good video. Here are the two things I ran (again see link above for text files with full FFmpeg ouput of each) :

  


  ffmpeg -i C :\Users\David\Videos\2020-06-23_17-39-32_corrupted.mkv -map 0:0 -c copy C :\Users\David\Videos\2020-06-23_17-39-32_corrupted_map0-0.mkv

  


  ffmpeg -i C :\Users\David\Videos\2020-06-23_17-39-32_corrupted.mkv -map 0:4 -c copy C :\Users\David\Videos\2020-06-23_17-39-32_corrupted_map0-4.mkv

  


  It seems the audio is intact, as I was able to map one of the audio streams into a wav file... although there seemed to be extra/repeated audio tacked onto where the video/audio should have ended...

  


  It looks to me like both video streams got written into stream 0:0, while stream 0:4 looks empty (because this map results in a very small file). However the thing that's weird (and maybe promising) is that when I play the corrupted file in VLC, it mostly looks like smeared digital colors, but if I click around to different times in the video, it sometimes shows good video, even though it won't show any good video if you just play it from the beginning.

  


  My life would saved if there is a way to extract good video/audio from this corrupted file. Any help would be greatly appreciated, thanks in advance !

  


• 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 !