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• How to use temporary files and replace the input when using ffmpeg in batch ?

  18 juin 2020, par Fabio Freitas

  What I did so far :

  



  I learned with this answer that I can use negative mapping to remove unwanted streams (extra audio, subtitles) from my video files.

  



  I them proceeded to apply it to a few dozen files in a folder using a simple for /r loop on Windows' cmd. Since I thought this process as some kind of trim, I didn't care about my original files and wanted ffmpeg to replace them, which of course it cannot.

  



  I tried to search a bit further and find ways to work around this issue without simply using a new destination an manually replacing files afterwards, but had no luck.

  



  However a lot of my findings seemed to indicate that ffmpeg has capabilities to use external temporary files for some of it's functions, even though I couldn't really find more onto it.

  



  What I want to do :

  



  So is there any way that I can make ffmpeg remove those extra streams and them replace the original file somehow. I'll also be needing to use this to multiple file, by I don't think this would be a big issue...

  



  I really need this to be done with ffmpeg, as learning the tool to it's full extent is a long-therm goal of mine and I want to keep working on that curve, but as for batch/cmd, I prefer it because I haven't properly learned a programming language yet (even if I often meddle with a few), but I would be happy to use suggestions of any kind for handling ffmpeg !

  



  Thank you !

  


• FFMPEG : Is there any property of FFMPEG, which make it start publishing video stream from IDR frame only

  27 mars 2019, par Shrishty Deorari

  I am using FFMPEG to publish video data (h264 encoded data) into Wowza streaming engine. My application captures and writes encoded video data frame by frame in a FIFO(named Pipe) and in another thread ffmpeg reads video data from that particular FIFO and then pushes to the cloud, everything goes smooth as long as network condition is good.

  In Bad network, frames start to drop as FFMPEG is not able to read and push frames to the cloud, in this loss if any I frame gets discarded I get green glitches in the video as expected.
  I am trying to get if there is any option/property in FFMPEG which I can use while pushing the data to the cloud, which will take care of GOP, so FFMPEG always pushes first IDR frame and then respective P frames to the Wowza streaming engine.

  Flow is :
  Application ----writes----->FIFO---reads--->FFMPEG-----pushes--->Wowza

  I am using FFMPEG binary. I can implement the GOP logic in my application, before writing the data in FIFO, but that can be done only If I can somehow know when FFMPEG stops reading data from FIFO due to a network condition and I am not sure I can do that, as it is a binary.

  Any help would be appreciated.

• Is ffmpeg giving incorrect frame count ?

  15 mai 2020, par trshmanx

  The videos Duration: 00:00:06.93 and 25 fps
If we do the math it's 173.25 (173 rounded) frames.
However this command ffmpeg -i video.mp4 -qscale:v 1 filename_%06d.jpg extracts 172 frames. Am I calculating or doing something wrong ?
I want to use this of some automation in my Python project.

  



  Edit :

  



  I do have video frame in 6.840000

  



  [FRAME]
media_type=video
stream_index=1
key_frame=0
pkt_pts=171000
pkt_pts_time=6.840000
pkt_dts=N/A
pkt_dts_time=N/A
best_effort_timestamp=171000
best_effort_timestamp_time=6.840000
pkt_duration=1000
pkt_duration_time=0.040000
pkt_pos=22689592
pkt_size=213060
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=P
coded_picture_number=169
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
color_range=tv
color_space=bt709
color_primaries=bt709
color_transfer=bt709
chroma_location=left
[/FRAME]


  



  My full frame dump here

  



  Edit 2 :

  



  My intention is to get the frames exactly, as when watching the video. I don't care about some frame being longer / shorter, audio longer etc. I tried to force the fps ffmpeg -i LUCKY_BRUNETTE.mp4 -vf fps=25 -qscale:v 1 filename_%06d.jpg but still got 172 frames.