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• Recover hevc encoded '.ts' files without SDP file or NAL block ?

  3 décembre 2023, par Anoduck

  In the process of trying to recover deleted video transport stream files from a storage device. The files are "hevc" encoded and when played output many errors of hevc: Could not find ref with POC 0 and when I attempt to repair them the output is PPS id out of range: 0 . There are no other file types on the storage device, especially no SDP file for which to extract the NAL block from. So, I am stumped as to how to go about acquiring the needed information to the frames to properly decode the files.

  


  ref : errors when decode H.264 frames using ffmpeg

  


  As mentioned previously, I did try to run ffmpeg -i corrupted_input.ts -map 0 -copy_unknown -c copy fixed.ts, and this is what generated the PPS id out of range: 0 error.

  


  If one of the recovered 'ts' files does contain the required SPS and PPS keyframe, it will be difficult pairing this file with any other file that might belong to it, since all files were recovered, renamed, and dumped into one large folder together. As per the default behavior with the recovery utility photorec.

  


• MOOV atom not found in MOV in 5 of 9 files from the same camera

  31 janvier 2023, par dnz

  I have 9 files : FHD001.MOV to FHD009.MOV. They come from 3 recordings : FHD001, FHD002-FHD007 and FHD008-FHD009. Apart from FHD001 and FHD007 all are about 2.3GB each.

  


  With ffmpeg I can transcode FHD002-FDD004 without problems.

  


  The other file give a moov atom not found error.

  


  I was able to repair FHD001 with ffmpeg by applying "-movflags faststart". But this does not work with the other files.

  


  The camera is not longer available and I do not remember brand or model.

  


  ffmpeg output of FHD002.MOV, the working file :

  


  Guessed Channel Layout for Input Stream #0.1 : stereo
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'FHD0002.MOV':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt
  Duration: 00:05:00.08, start: 0.000000, bitrate: 61534 kb/s
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p(pc, bt470bg/unknown/unknown), 3840x2160, 60121 kb/s, 25 fps, 25 tbr, 60k tbn, 60k tbc (default)
    Metadata:
      handler_name    : Video Handler
      encoder         : iCatch AVCC
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 44100 Hz, stereo, s16, 1411 kb/s (default)
    Metadata:
      handler_name    : Audio Handler


  


  ffmpeg output of FHD001.MOV when applying -movflags faststart

  


  Guessed Channel Layout for Input Stream #0.1 : stereo
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'FHD0001.MOV':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt
  Duration: 00:00:06.20, start: 0.000000, bitrate: 61515 kb/s
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p(pc, bt470bg/unknown/unknown), 3840x2160, 60123 kb/s, 25 fps, 25 tbr, 60k tbn, 60k tbc (default)
    Metadata:
      handler_name    : Video Handler
      encoder         : iCatch AVCC
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 44100 Hz, stereo, s16, 1411 kb/s (default)
    Metadata:
      handler_name    : Audio Handler
Output #0, mov, to 'vid1.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt
    encoder         : Lavf58.18.104
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p(pc, bt470bg/unknown/unknown), 3840x2160, q=2-31, 60123 kb/s, 25 fps, 25 tbr, 60k tbn, 60k tbc (default)
    Metadata:
      handler_name    : Video Handler
      encoder         : iCatch AVCC
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 44100 Hz, stereo, s16, 1411 kb/s (default)
    Metadata:
      handler_name    : Audio Handler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
[mov @ 000001ba0d881540] Starting second pass: moving the moov atom to the beginning of the file
frame=  155 fps= 51 q=-1.0 Lsize=   46559kB time=00:00:06.16 bitrate=61916.6kbits/s speed=2.01x
video:45503kB audio:1051kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.009488%


  


  Output for FHD005.MOV

  


  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000236d7269880] moov atom not found
FHD0005.MOV: Invalid data found when processing input


  


  I tried to apply -movflags faststart to get a functioning video file

  


• ImageJ / Fiji shows wrong number of frames in video (FFMPEG import)

  28 avril 2023, par locoric_polska

  I am counting the number of animals in a an area using Fiji. I import the video through the FFMPEG plug-in (videos are mp4 with mpeg-4 codec). However, I noticed that when I import the videos Fiji uploads the wrong number of frames, and I cannot understand why and how.

  


  An example. I have a video shot at 25fps which is 1582s long. If I do the calculations the video should have 39550 frames in total (1582*25). When I open it through a Computer vision package in R, I see that the video correctly contains 39550 frames. However, when loaded in Fiji, the shown number of frames is 49511. So Fiji is adding 9961 frames to the video. This is consistent across all videos that are recorded in 25fps, while it does not appear in videos shot at 24fps.

  


  Curiously, I found that the ratio between the number of frames read by Fiji and the 'real' number of frames is consistent between 0.79 and 0.80. This makes me think that Fiji is expecting the video to be 30fps and (possibly) duplicating frames to adjust the video to this assumption.

  


  Unfortunately, I discovered all this after finishing my analysis and while trying to merge this dataset with another obtained through CV. The number of frame does not match between datasets and I am not sure how to solve this.

  


  Any help would be greatly appreciated !!

  


  An idea is to multiply all the frame numbers by 0.8 to adjust them to the old assumption. This solution assumes that Fiji is duplicating frames throughout the video in a consistent way