[MPlayer-advusers] mencoder reads wrong frame rate flag fromQuicktime files

[Dominic Bird]

-----Original Message-----
From: mplayer-advusers-bounces at mplayerhq.hu
[mailto:mplayer-advusers-bounces at mplayerhq.hu] On Behalf Of Dominic Bird
Sent: 06 July 2010 15:13
To: MPlayer-advusers at mplayerhq.hu
Subject: [MPlayer-advusers] mencoder reads wrong frame rate flag
fromQuicktime files

Hi everyone,

 

I've noticed something odd when reading Quicktime files with mencoder.
Specifically broadcast HD formats such as ProRes and DVCPRO HD.
Quicktime seems to flag these files as VFR (even though they are not)
and then flags them with odd frame rate info. Is there a way to read the
frame rate correctly when encoding with mencoder without forcing the
frame rate with a command?

 

Heres the flags from mediainfo on a 23.976 ProRes file (I know its
23.976  as I captured the file with FCP):

 

Frame rate mode                  : Variable

Frame rate                       : 24.014 fps

Minimum frame rate               : 15.984 fps

Maximum frame rate               : 162.000 fps

 

Mencoder reads this as 15.984fps. If I force it using the -fps 23.976
command I can encode it without skipping frames but I need to set it up
as a script for encoding thousands of files at different frame rates. As
there is no consistency with what the actual frame rate is it's hard to
write something without rounding up the frame rate to the nearest whole
number or something but that would not work when trying to differentiate
between 23.976 and 24 material, or 29.97 and 30 material.

 

Is there a command in mencoder that tries to work out the frame rate of
the file more accurately?

 

Thanks in advance! Heres the command im using FYI:

 

mencoder -demuxer mov \\xxx\testmovhd2398.mov -o \\xxx\testmovhd2398.flv
-vf pp=fd,scale=1280:720 -af channels=2,format=s16le,resample=44100 -mc
0 -ovc x264 -x264encopts
global_header:level_idc=30:bframes=0:bitrate=2048:preset=superfast -oac
faac -faacopts mpeg=4:object=2:br=128:raw -of lavf

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I think i've found it. Mencoder should read the 'Time Scale' flag rather
than any frame rate flags with VFR material. If you use ExifTool on a
Quicktime file the 'Time Scale' data = the frame rate. See below on 2
test files. First is 23.976, second is 29.97.

ExifTool Version Number         : 8.24
File Name                       : testmovhd2398.mov
File Type                       : MOV
MIME Type                       : video/quicktime
Time Scale                      : 23976	
Duration                        : 9.26 s
Compressor ID                   : apch
Source Image Width              : 1920
Source Image Height             : 1080
Video Frame Rate                : 24.013

ExifTool Version Number         : 8.24
File Name                       : testmovhd2997.mov
File Type                       : MOV
MIME Type                       : video/quicktime
Time Scale                      : 2997
Duration                        : 8.21 s
Compressor ID                   : apch
Source Image Width              : 1920
Source Image Height             : 1080
Video Frame Rate                : 29.91