[FFmpeg-user] backtrack parameters from existing file

[Scott Goldman]

   ----- Original Message -----From: "Scott Goldman"
<scottg at emailhosting.com> Sent: Tue, January 8, 2013 18:11Subject: Re:
[FFmpeg-user] backtrack parameters from existing file    ----- Original
Message -----From: "Carl Eugen Hoyos" <cehoyos at ag.or.at> Sent: Tue,
January 8, 2013 17:23Subject: Re: [FFmpeg-user] backtrack parameters
from existing file
Scott Goldman <scottg <at> emailhosting.com> writes:

> So i've discovered what my issue really is. I'm trying to transcode from
> an MXF file created by QUANTEL 3.6.  This version of their power portal
> incorrectly set the edit rate as 59.97 but is in really 29.97.  so my
> transcode is running at double speed.

Please provide a sample if this is reproducible with FFmpeg.

> I would like to use the -r 29.97
> before the -i, but that doesnt work and when i add -force_fps -r 29.97,
> ffmpeg reports Option framerate not found.

>This is a (common) misunderstanding:
>MPlayer used to rely on the framerate to calculate
>timestamps, FFmpeg mostly only provides the frame-rate
>for informational purpose (there are exceptions, but
>mxf is not one of them).

>Or in other words: You cannot fix this problem by
>providing an option, please test ffmpeg and if
>it fails, please provide complete, uncut
>console output (and a sample).

>Carl Eugen

Sorry, i missed this email. i cant send the clip, but i full output is
below.  you will see that ffmeg picks up that the m,xf is at 59.97, which
is a mistake on Quantels part.

the quesiton is how to get ffmpeg to ignore that and belive me (from the
command line)...

i guess the alternative would be to compile a version of ffmpeg that 1/2's
the input speed all the time.  how difficult would that be?


[bassnas01: SU: share/Cache 1805] ffmpeg  -y -r 29.97 -i  Quantel_3.6.mxf 
 -vcodec libx264 -vpre libx264-superfast -r 29.97  -b 3000k -maxrate 8000k
-bufsize 1000k  -threads 0 -s 1280x720   Quantel_3.6.ssg.mp4
FFmpeg version 0.6.5, Copyright (c) 2000-2010 the FFmpeg developers
  built on Jan 29 2012 23:55:02 with gcc 4.1.2 20080704 (Red Hat 4.1.2-51)
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64
--mandir=/usr/share/man --incdir=/usr/include --disable-avisynth
--extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
-fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC'
--enable-avfilter --enable-avfilter-lavf --enable-libdirac
--enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libgsm
--enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libx264 --enable-gpl
--enable-nonfree --enable-postproc --enable-pthreads --enable-shared
--enable-swscale --enable-vdpau --enable-version3 --enable-x11grab
  libavutil     50.15. 1 / 50.15. 1
  libavcodec    52.72. 2 / 52.72. 2
  libavformat   52.64. 2 / 52.64. 2
  libavdevice   52. 2. 0 / 52. 2. 0
  libavfilter    1.19. 0 /  1.19. 0
  libswscale     0.11. 0 /  0.11. 0
  libpostproc   51. 2. 0 / 51. 2. 0
Input #0, mxf, from 'Quantel_3.6.mxf':
  Duration: 00:00:16.13, start: 0.000000, bitrate: 237417 kb/s
    Stream #0.0: Video: dvvideo, yuv422p, 960x720, 59.94 fps, 59.94 tbr,
59.94 tbn, 59.94 tbc
    Stream #0.1: Audio: pcm_s16le, 48000 Hz, 1 channels, s16, 768 kb/s
    Stream #0.2: Audio: pcm_s16le, 48000 Hz, 1 channels, s16, 768 kb/s
    Stream #0.3: Audio: pcm_s16le, 48000 Hz, 1 channels, s16, 768 kb/s
    Stream #0.4: Audio: pcm_s16le, 48000 Hz, 1 channels, s16, 768 kb/s
[libx264 @ 0x13b31980]using cpu capabilities: MMX2 SSE2Fast SSSE3
FastShuffle SSE4.2
[libx264 @ 0x13b31980]profile High, level 3.1
[libx264 @ 0x13b31980]264 - core 107 - H.264/MPEG-4 AVC codec - Copyleft
2003-2010 - http://www.videolan.org/x264.html - options: cabac=1 ref=1
deblock=1:0:0 analyse=0x3:0x3 me=dia subme=1 psy=1 psy_rd=0.00:0.00
mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0
deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 sliced_threads=0
nr=0 decimate=1 interlaced=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=250
keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=0
bitrate=3000 ratetol=1.3 qcomp=0.60 qpmin=10 qpmax=51 qpstep=4
vbv_maxrate=8000 vbv_bufsize=1000 ip_ratio=1.41 pb_ratio=1.25 aq=1:1.00
nal_hrd=none
Output #0, mp4, to 'Quantel_3.6.ssg.mp4':
  Metadata:
    encoder         : Lavf52.64.2
    Stream #0.0: Video: libx264, yuv420p, 1280x720, q=10-51, 3000 kb/s,
2997 tbn, 29.97 tbc
    Stream #0.1: Audio: libfaac, 48000 Hz, 1 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
frame=  484 fps= 44 q=-1.0 Lsize=    6073kB time=16.08
bitrate=3093.6kbits/s dup=0 drop=483
video:5802kB audio:252kB global headers:0kB muxing overhead 0.317652%
[libx264 @ 0x13b31980]frame I:3     Avg QP:24.12  size: 42655
[libx264 @ 0x13b31980]frame P:335   Avg QP:26.53  size: 14870
[libx264 @ 0x13b31980]frame B:146   Avg QP:28.91  size:  5696
[libx264 @ 0x13b31980]consecutive B-frames: 40.3% 56.5%  3.1%  0.0%
[libx264 @ 0x13b31980]mb I  I16..4: 30.4% 44.7% 25.0%
[libx264 @ 0x13b31980]mb P  I16..4: 14.3% 17.6%  1.4%  P16..4: 41.7%  0.0%
 0.0%  0.0%  0.0%    skip:25.0%
[libx264 @ 0x13b31980]mb B  I16..4:  3.6%  2.7%  0.1%  B16..8: 30.3%  0.0%
 0.0%  direct: 6.7%  skip:56.6%  L0:36.3% L1:52.4% BI:11.3%
[libx264 @ 0x13b31980]final ratefactor: 27.64
[libx264 @ 0x13b31980]8x8 transform intra:51.8% inter:59.2%
[libx264 @ 0x13b31980]coded y,uvDC,uvAC intra: 34.6% 24.9% 5.3% inter:
15.1% 9.7% 0.9%
[libx264 @ 0x13b31980]i16 v,h,dc,p: 30% 37% 22% 10%
[libx264 @ 0x13b31980]i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 10% 28% 31%  4%  6% 
3%  6%  3%  9%
[libx264 @ 0x13b31980]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 15% 36% 14%  4%  8% 
4%  6%  4%  8%
[libx264 @ 0x13b31980]i8c dc,h,v,p: 57% 26% 14%  3%
[libx264 @ 0x13b31980]kb/s:2943.02


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