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• Simples loop to iterate over files and send them to ffmpeg

  25 octobre 2019, par user2752471

  I want to do a shell script that will iterate over several video files in a directory, send everyone of them to ffmpeg, that will then reencode each one, producing a reencoded file that will have the same name as the original, except with .avi extension instead .mkv or .mp4.

  I found a fairly simple script in another topic here on SO, tried to change it slightly to take into account the file extension and the destination directory.

  However my script only produces countless "anything : No such file or directory"

  Here is it :

  $ for f in $(find -type f -name *.mkv); do ffmpeg -n -i "$f" -c:v copy ".$f" ; done

  And these is the ffmpeg command that I usually use :

  ffmpeg -y -i  -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 1 -an -f avi /dev/null && ffmpeg -i -c:a libmp3lame -b:a 48k -ac 1 -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 2  .avi

  So I need to identify what is incorrect in the first script, that is considering each small word of the file’s name as a file, and then change it as to add all these ffmpeg parameters.

  Somethings that I do not understand in the script :

  1)Are the -type and f in find command necessary. From what I read of the documentation, all it does is to tell find that it shall look for normal files, something that seems irrelevant for my case. When I use find, I do : find starting dir -name filename. So do I have to keep it ?

  2)What -n means for ffmpeg ? I am currently without a man entry for ffmpeg. Is it necessary for my needs ?

  3)Do I need to have "" around $f ? What it does ?

  4)As far as I understand $ denotes a variable. But what the "f" after it does ? Do I need it ?

  5)The " ;" after the closing ")" and the ".$f" are necessary ? The first is used to indicate the end of the for loop,and the second the end of the ffmpeg command ?

  6)The "do" and the "does" are also necessary for the same motives behind the " ;"

  Here is my attempt of the ffmpeg part of the script. Please tell me what to change on it, as in the find part of it.

  do ffmpeg -n -y -i "$f.mkv" -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 1 -an -f avi /dev/null && ffmpeg -n -i "$f" -c:a libmp3lame -b:a 48k -ac 1 -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 2  ".$f.avi" ; done

  If I would like the script to also look for ".mp4" besides ".mkv" how I would need to change it ?

  Thanks for any input.

• avcodec/mips : Improve hevc uni-w horiz mc msa functions

  9 octobre 2017, par Kaustubh Raste

  avcodec/mips : Improve hevc uni-w horiz mc msa functions
  Load the specific destination bytes instead of MSA load and pack.
  
  Pack the data to half word before clipping.
  
  Use immediate unsigned saturation for clip to max saving one vector register.
  Signed-off-by : Kaustubh Raste <kaustubh.raste@imgtec.com>
  
  Reviewed-by : Manojkumar Bhosale <Manojkumar.Bhosale@imgtec.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mips/hevc_macros_msa.h
  • [DH] libavcodec/mips/hevc_mc_uniw_msa.c

• FFMPEG stereo track stops capturing at random times during a capture session

  26 mai 2022, par mrwassen

  I am currently working on building a workflow to capture and archive a large stash of family and friends PAL and NTSC VHS tapes. The hardware setup is as follows :

  


  

  • JVC HR-7860S VCR

  


  • s-video / RCA audio >

  


  • ADVC-3000 converter

  


  • SDI / BNC cable >

  


  • Blackmagic Decklink Mini Recorder 4K PCIe card

  


  • installed in a fairly hi-spec windows machine : AMD Ryzen 9 5900X 3.7 Ghz base 12 core, GEFORCE RTX 3060 12 gB, 32 gB ram

  


  


  The plan is to capture to lossless AVI, then drop into an NLE (Vegas Pro v.16) to do a minimal amount of cleanup / trimming, then render to a more compressed video format (TBD) for upload to AWS S3 accessible through a family website.

  


  The issue I am having is that when I run the capture using ffmpeg/directshow e.g. for a perfectly fine 90 min. PAL tape, at some random point of time during the capture one of the 2 stereo channels just stops capturing. This has happened with all of the tapes I have tested so far, and it happens at different times during the same video. I have examined the frames surrounding points in time when this happens, and it doesn't correlate to any transitions or jitter, but often just randomly in the middle of a perfectly smooth scene. Once the one channel stops capturing it never starts back up again during that capture session.

  


  The ADVC-3000 and the VCR are both showing both stereo channels playing normally throughout the capture. The windows machine running the capture hardly breaks a sweat at any time, and the transfer easily keeps up constantly showing a speed = 1x which I assume means nothing lagging. Also there are no video/audio sync issues at any point in time even towards the end of long tapes e.g. 90 mins.

  


  I am fairly new at ffmpeg, so I have spent extensive amounts of time reading up on forum posts and experimenting and have ended up with the following syntax :

  


  ffmpeg -y -f dshow -rtbufsize 2000M -i video="Blackmagic WDM Capture":audio="Blackmagic WDM Capture" -codec:v v210 -pix_fmt yuv422p -codec:a pcm_s16le -b:a 128k -t 02:00:00 -r 25 -threads 4 -maxrate 2500k -filter:a "volume=1.5" output_v210_audio.avi


  


  The capture runs without a single dropped frame, the only error I am getting when launching (and perhaps this is a smoking gun ?) is :

  


  


  "Non-monotonous DTS in output stream 0:1 ; previous : 0, current : -30 ;
changing to 1. This may result in incorrect timestamps in the output
file."

  


  


  I have tried to troubleshoot this in the hopes that it is tied to my issue but so far without luck.

  


  Hoping somebody can help correct or modify my command line or perhaps other ideas to help resolve the issue.