Search found 183 matches

by pandy
Mon Jul 15, 2019 5:04 pm
Forum: Usage
Topic: Splitting a video file according to black frames
Replies: 1
Views: 162

Re: Splitting a video file according to black frames

I think this is not easy task, you can save list of black frames but still splitting file will not work if split point belongs to non IDR (I) frame, also closed GOP is almost mandatory to nicely cut video at IDR frame. You may need to navigate to IDR following your cut and cut video at this point an...
by pandy
Mon Jul 15, 2019 4:52 pm
Forum: Usage
Topic: hevc_qsv producing empty file
Replies: 3
Views: 312

Re: hevc_qsv producing empty file

Check this: http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/cloud-computing-quicksync-video-ffmpeg-white-paper.pdf - bit old, also search for current Intel API references (perhaps check ffmpeg hevc_qsv source) - from my perspective only NVidia NVEnc provided working solution...
by pandy
Wed Jul 10, 2019 7:19 pm
Forum: Usage
Topic: Completly cut a frequency range
Replies: 12
Views: 470

Re: Completly cut a frequency range

I recall CD protection by removing (notch filter) frequency 315 or 3150Hz (this was like 25 years ago so perhaps this is not correct frequency but for sure butchering audio by notch filter). And modulating phase with proper way (i.e. https://en.wikipedia.org/wiki/Process_gain) is extremely robust an...
by pandy
Wed Jul 10, 2019 7:06 pm
Forum: Usage
Topic: showspectrumpic and background color
Replies: 5
Views: 446

Re: showspectrumpic and background color

Black as transparent and overlay on top white field (but spectrum "fringes" may have bleed to black i.e. not nicely looking on white). Had similar problem in past trying to overlay transparently oscilogram - cli is probably suboptimal and poor but works for me and may works for you: @set name=%1 @ff...
by pandy
Tue Jul 09, 2019 5:48 pm
Forum: Usage
Topic: Completly cut a frequency range
Replies: 12
Views: 470

Re: Completly cut a frequency range

Thank you for your explanation you have been super helpfull. It would probably help if you understood the context in which this is needed for: Im developing a system to watermark audio using complete frequecny cuts cutting 100hz at the most dominant frequency then using showspectrum and image recog...
by pandy
Mon Jul 08, 2019 8:03 pm
Forum: Usage
Topic: Offset a movie of a specific frames number
Replies: 1
Views: 132

Re: Offset a movie of a specific frames number

to perform accurate seek you need very short and closed GOP - you can't access GOP beyond I (IDR) frame boundaries.
by pandy
Mon Jul 08, 2019 7:49 pm
Forum: Usage
Topic: Completly cut a frequency range
Replies: 12
Views: 470

Re: Completly cut a frequency range

assuming your other questions are still valid and you searching for bandstop filter 10Hz wide and frequency centre 100Hz check something like this: firequalizer=gain_entry='entry(15,-INF); entry(20,0); entry(94,0); entry(95, -INF); entry(105, -INF); entry(106,0); entry(22000,0); entry(23000, -INF)' ...
by pandy
Mon Jul 08, 2019 7:39 pm
Forum: Usage
Topic: FFmpeg (PC) vs FFmpeg (Android)
Replies: 1
Views: 148

Re: FFmpeg (PC) vs FFmpeg (Android)

Depends on used encoder your output may not be bit exact (commonly on mobile devices integer encoder implementation is preferred).
by pandy
Sat Jul 06, 2019 5:27 pm
Forum: Usage
Topic: Apply BiQuad filter to wav at certian timespans
Replies: 12
Views: 899

Re: Apply BiQuad filter to wav at certian timespans

Perhaps you want bandpass filter? Also from zeranoe you can download latest devel version which have timeline support. I think bandstop, probably to remove second harmonics of 50Hz (i.e. 100Hz) - fullwave rectifier or something similar, he need bandstop (notch) filter - best option is fir filter or...