[FFmpeg-user] Default output fps vs fps filter @ 30fps

2019-10-20 Thread Hans Carlson 
I have an h264/vorbis video at 1k fps and want to convert it to mpeg2/ac3 
at 30 fps.  If I don't use the fps filter ffmpeg appears to automatically 
convert the output to 30 fps (which I assume is the default -r value), but 
the following warnings are displayed:


  More than 1000 frames duplicated
  More than 1 frames duplicated

If I use the fps filter (fps=fps=30), then those warnings are not 
displayed and there's no indication of duplicated (or dropped) frames... 
although I assume there must have been.


I can't see any obvious difference between the 2 output files (although I 
haven't watched both completely through), so I'm just curious if there IS 
any appreciable difference for this video.


Is there any advantage (or disadvantage) to using the fps filter vs the -r 
option in this particular case?


Here's full output for both commands:

$ ffmpeg -i TEST.mkv -codec:v mpeg2video -b:v 16384k -bufsize 4096k -maxrate 
3k -codec:a ac3 -b:a 448k -ar 48000 -f vob TEST-default.mpg
ffmpeg version N-95488-g09581f7923 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (GCC)
  configuration: --enable-gpl --enable-nonfree --enable-libass 
--enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus 
--enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 
--enable-libx265 --enable-openssl
  libavutil  56. 35.101 / 56. 35.101
  libavcodec 58. 59.102 / 58. 59.102
  libavformat58. 33.100 / 58. 33.100
  libavdevice58.  9.100 / 58.  9.100
  libavfilter 7. 63.100 /  7. 63.100
  libswscale  5.  6.100 /  5.  6.100
  libswresample   3.  6.100 /  3.  6.100
  libpostproc55.  6.100 / 55.  6.100
Input #0, matroska,webm, from 'TEST.mkv':
  Metadata:
ENCODER : Lavf57.71.100
  Duration: 00:58:41.47, start: 0.00, bitrate: 2190 kb/s
Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1600x900 
[SAR 1:1 DAR 16:9], 1k fps, 30 tbr, 1k tbn, 60 tbc (default)
Metadata:
  DURATION: 00:58:41.43400
Stream #0:1: Audio: vorbis, 48000 Hz, stereo, fltp (default)
Metadata:
  DURATION: 00:58:41.47400
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> mpeg2video (native))
  Stream #0:1 -> #0:1 (vorbis (native) -> ac3 (native))
Press [q] to stop, [?] for help
Output #0, vob, to 'TEST-default.mpg':
  Metadata:
encoder : Lavf58.33.100
Stream #0:0: Video: mpeg2video (Main), yuv420p, 1600x900 [SAR 1:1 DAR 
16:9], q=2-31, 16384 kb/s, 30 fps, 90k tbn, 30 tbc (default)
Metadata:
  DURATION: 00:58:41.43400
  encoder : Lavc58.59.102 mpeg2video
Side data:
  cpb: bitrate max/min/avg: 3000/0/16384000 buffer size: 4096000 
vbv_delay: N/A
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 448 kb/s (default)
Metadata:
  DURATION: 00:58:41.47400
  encoder : Lavc58.59.102 ac3
More than 1000 frames duplicated  73126kB time=00:03:11.54 bitrate=3127.4kbits/s dup=985 drop=0 speed= 6.8x 
More than 1 frames duplicated510586kB time=00:13:46.84 bitrate=5058.7kbits/s dup=9998 drop=0 speed=6.22x 
frame=105644 fps=198 q=2.0 Lsize= 1967088kB time=00:58:41.50 bitrate=4576.0kbits/s dup=31190 drop=0 speed=6.58x 
video:1749220kB audio:192582kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.302177%


$ ffmpeg -i TEST.mkv -codec:v mpeg2video -b:v 16384k -bufsize 4096k -maxrate 
3k -codec:a ac3 -b:a 448k -ar 48000 -vf fps=fps=30 -f vob TEST-fpsfilter.mpg
ffmpeg version N-95488-g09581f7923 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (GCC)
  configuration: --enable-gpl --enable-nonfree --enable-libass 
--enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus 
--enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 
--enable-libx265 --enable-openssl
  libavutil  56. 35.101 / 56. 35.101
  libavcodec 58. 59.102 / 58. 59.102
  libavformat58. 33.100 / 58. 33.100
  libavdevice58.  9.100 / 58.  9.100
  libavfilter 7. 63.100 /  7. 63.100
  libswscale  5.  6.100 /  5.  6.100
  libswresample   3.  6.100 /  3.  6.100
  libpostproc55.  6.100 / 55.  6.100
Input #0, matroska,webm, from 'TEST.mkv':
  Metadata:
ENCODER : Lavf57.71.100
  Duration: 00:58:41.47, start: 0.00, bitrate: 2190 kb/s
Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1600x900 
[SAR 1:1 DAR 16:9], 1k fps, 30 tbr, 1k tbn, 60 tbc (default)
Metadata:
  DURATION: 00:58:41.43400
Stream #0:1: Audio: vorbis, 48000 Hz, stereo, fltp (default)
Metadata:
  DURATION: 00:58:41.47400
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> mpeg2video (native))
  Stream #0:1 -> #0:1 (vorbis (native) -> ac3 (native))
Press [q] to stop, [?] for help
Output #0, vob, to 'TEST-fpsfilter.mpg':
  Metadata:
encoder : Lavf58.33.100
Stream #0:0: Video: mpeg2video (Main), yuv420p, 1600x900

Re: [FFmpeg-user] Default output fps vs fps filter @ 30fps

2019-10-20 Thread Carl Eugen Hoyos 


> Am 20.10.2019 um 23:05 schrieb Hans Carlson :
> 
> Is there any advantage (or disadvantage) to using the fps filter vs the -r 
> option in this particular case?

The main difference between the fps filter and the constant frame rate output 
that can be forced by the command line utility is that the filter is less 
verbose.
The algorithms are not equally greedy but it is likely that this makes little 
or no difference for your use case.

Carl Eugen
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Re: [FFmpeg-user] Default output fps vs fps filter @ 30fps

2019-10-20 Thread Hans Carlson 

On Sun, 20 Oct 2019, Carl Eugen Hoyos wrote:


Am 20.10.2019 um 23:05 schrieb Hans Carlson :

Is there any advantage (or disadvantage) to using the fps filter vs the 
-r option in this particular case?


The main difference between the fps filter and the constant frame rate 
output that can be forced by the command line utility is that the filter 
is less verbose. The algorithms are not equally greedy but it is likely 
that this makes little or no difference for your use case.


Ah, so the fps filter *could* display the same/similar kind of "frames 
duplicated" messages, it just doesn't.  Thanks Carl, that's kind of what I 
suspected.


PS. I do realize there may be instances (eg. different codecs and/or 
increasing fps) where the filter vs -r option could make more of a 
difference.  But in this instance, as you say, probably nothing noticeable.

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