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• Detecting Successful Conversion with ffmpeg

  22 février 2017, par J M

  I have code that scans a file system for videos files encoded with H.264 and re-encodes them with H.265. It runs pretty much on its own constantly, generating various log files for me to review periodically.

  One thing that I want to further improve is the successful conversion detection. Right now, a file returns as being successfully converted after it meets these criteria/checks :

  1. The output file exists
  2. ffprobe can detect that the output file is in hevc format
  3. The duration of the output file matches that of the input file (within 3 seconds)
  4. The length of the output file is greater than 30 MB (it’s rare that I have a video so short where after conversion it is less than this, usually this happens when an error occurs or conversion terminates early).

  Obviously, this is rather computationally intense as there are many file checks to confirm all of this information. I do this because if the file is detected as successful conversion, the old file is overwritten and the new converted file takes it’s place. I don’t want to overwrite a file because I overlooked a scenario where I think conversion is successful but was in fact not. The files are under a crashplan constant backup, so I don’t lose them, but I also do not go through and review every file.

  So, my basic question is if you see any area of improvement for this detection. My goal is to determine, to my best extent, if after conversion the video remains "playable". So deciding programmatically how/what that means is what I’m attempting to do.

  I can post code if you want it (powershell), but the question seems independent of actual program language choice.

• Anomalie #3864 (Fermé) : Feuille de style lorsque le bouton _BOUTON_MODE_IMAGE = false

  23 novembre 2016, par Laurent Lefebvre

  Juste quelques chipotages de styles lorsque le bouton portfolio est désactivé.
  Dans ce cas, les boutons "détacher", et autres outils collent au descriptif du dessus. Il faut donc modifier légèrement la feuille de style "style_prive_plugin_medias.html"

  ligne 160 :
  .portfolios .item .infos display:block ; margin-bottom : 0.7em ;
  .portfolios .item div.mode display:inline-block ;clear :#GETright ; margin-top : 0 ;

  ligne 173 :
  .portfolios .item .actions a.editbox visibility : visible ; opacity : 1 ; float : right ; margin-top : .2em ; font-weight : bold ; margin-right : .5em ;

• ffmpeg - HLS stream audio error between segmets

  2 février 2019, par Carl

  I have a huge amount of mp4 files to create HLS segments from, more than 200 hours worth of files. I don’t see the point of re-encoding these videos because they are already in mp4 format. I’m using the following command which copies the video into segments instead of encoding it again.

  ffmpeg -i filename.mp4 -codec: copy -start_number 0 -hls_time 4 -hls_list_size 0 -f hls filename.m3u8

  The problem is when it comes to stitching these segments, I’m getting micro audio errors between segments. It’s hard to explain but imagine somebody turning audio off for 0.1 seconds. I doesn’t happen in all of the segments but in 20%-30% of them. Is there anything I can do stop these errors from popping up apart from reencoding all the videos. There are no problems with video btw.

  Here’s media info from one of the files :

  General
  Complete name : C :\video_test\video_file.mp4
  Format : MPEG-4
  Format profile : Base Media / Version 2
  Codec ID : mp42 (isom/iso2/avc1/mp41/mp42)
  File size : 45.7 MiB
  Duration : 7 min 34 s
  Overall bit rate mode : Variable
  Overall bit rate : 844 kb/s
  Writing application : Lavf53.32.100
  

  Video
  ID : 1
  Format : AVC
  Format/Info : Advanced Video Codec
  Format profile : High@L4
  Format settings, CABAC : Yes
  Format settings, RefFrames : 8 frames
  Codec ID : avc1
  Codec ID/Info : Advanced Video Coding
  Duration : 7 min 34 s
  Bit rate : 767 kb/s
  Width : 1 280 pixels
  Height : 720 pixels
  Display aspect ratio : 16:9
  Frame rate mode : Constant
  Frame rate : 30.000 FPS
  Color space : YUV
  Chroma subsampling : 4:2:0
  Bit depth : 8 bits
  Scan type : Progressive
  Bits/(Pixel*Frame) : 0.028
  Stream size : 41.5 MiB (91%)
  Writing library : x264 core 136
  Encoding settings : cabac=1 / ref=8 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=6 / psy=0 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=48 / lookahead_threads=5 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=0 / keyint=60 / keyint_min=30 / scenecut=0 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

  Audio
  ID : 2
  Format : AAC
  Format/Info : Advanced Audio Codec
  Format profile : LC
  Codec ID : 40
  Duration : 7 min 34 s
  Bit rate mode : Variable
  Bit rate : 72.0 kb/s
  Maximum bit rate : 96.0 kb/s
  Channel(s) : 2 channels
  Channel positions : Front : L R
  Sampling rate : 44.1 kHz
  Frame rate : 43.066 FPS (1024 SPF)
  Compression mode : Lossy
  Stream size : 3.92 MiB (9%)
  Language : English
  Default : Yes
  Alternate group : 1
  

  Edit : I just tried copying video and reencoding the audio with the following command but problem still persists.

  ffmpeg -i filename.mp4 -vcodec copy -c:a aac -ar 48000 -b:a 128k -start_number 0 -hls_time 4 -hls_list_size 0  -f hls filename.m3u8