[MEncoder-users] Questions about fps and synch for vintage QuickTime movies

[Mike Spreitzer]

OK, ffmpeg is great.  I can transcode with it, and it does not lose sync. 
However, I am a bit puzzled by one complaint.  I tried exactly the command 
you suggested, and it complained that the original video frame rate is 600 
per second!  Here is a typescript:

$ ffmpeg -i Problem1.mov -qscale 2 out.avi
ffmpeg version 0.7.8, Copyright (c) 2000-2011 the FFmpeg developers
  built on Feb 20 2012 19:25:22 with gcc 4.2.1 (Apple Inc. build 5666) 
(dot 3)
  configuration: --prefix=/opt/local --enable-gpl --enable-postproc 
--enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis 
--enable-libtheora --enable-libdirac --enable-libschroedinger 
--enable-libopenjpeg --enable-libxvid --enable-libx264 --enable-libvpx 
--enable-libspeex --mandir=/opt/local/share/man --enable-shared 
--enable-pthreads --cc=/usr/bin/gcc-4.2 --arch=x86_64 --enable-yasm
  libavutil    50. 43. 0 / 50. 43. 0
  libavcodec   52.123. 0 / 52.123. 0
  libavformat  52.111. 0 / 52.111. 0
  libavdevice  52.  5. 0 / 52.  5. 0
  libavfilter   1. 80. 0 /  1. 80. 0
  libswscale    0. 14. 1 /  0. 14. 1
  libpostproc  51.  2. 0 / 51.  2. 0

Seems stream 0 codec frame rate differs from container frame rate: 600.00 
(600/1) -> 30.00 (30/1)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Problem1.mov':
  Metadata:
    major_brand     : qt 
    minor_version   : 537199360
    compatible_brands: qt 
    creation_time   : 2012-02-23 07:18:23
  Duration: 00:00:31.08, start: 0.000000, bitrate: 9615 kb/s
    Stream #0.0(eng): Video: rawvideo, yuyv422, 160x120, 8203 kb/s, 26.71 
fps, 30 tbr, 600 tbn, 600 tbc
    Metadata:
      creation_time   : 2012-02-23 07:18:23
    Stream #0.1(eng): Audio: pcm_s16be, 44100 Hz, 2 channels, s16, 1411 
kb/s
    Metadata:
      creation_time   : 2012-02-23 07:18:23
Incompatible pixel format 'yuyv422' for codec 'mpeg4', auto-selecting 
format 'yuv420p'
[buffer @ 0x101b39f40] w:160 h:120 pixfmt:yuyv422 tb:1/1000000 sar:0/1 
sws_param:
[buffersink @ 0x101b3a180] auto-inserting filter 'auto-inserted scaler 0' 
between the filter 'src' and the filter 'out'
[scale @ 0x101b3a400] w:160 h:120 fmt:yuyv422 -> w:160 h:120 fmt:yuv420p 
flags:0x4
Output #0, avi, to 'out.avi':
  Metadata:
    major_brand     : qt 
    minor_version   : 537199360
    compatible_brands: qt 
    creation_time   : 2012-02-23 07:18:23
    ISFT            : Lavf52.111.0
    Stream #0.0(eng): Video: mpeg4, yuv420p, 160x120, q=2-31, 200 kb/s, 30 
tbn, 30 tbc
    Metadata:
      creation_time   : 2012-02-23 07:18:23
    Stream #0.1(eng): Audio: mp2, 44100 Hz, 2 channels, s16, 64 kb/s
    Metadata:
      creation_time   : 2012-02-23 07:18:23
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop, [?] for help
frame=  830 fps=  0 q=2.0 Lsize=    4631kB time=00:00:29.90 
bitrate=1268.8kbits/s 
video:4328kB audio:243kB global headers:0kB muxing overhead 1.315741%
$ 

I have not got permission from the (deceased) subjects of these movies to 
post them publicly, and can not produce new test movies in the same way 
because the equipment I originally used has decayed.

BTW, I remembered that there was a step I omitted from my original 
description.  What actually happened is I took images of the old mac disks 
(created, I think, in System 7.5.something) and mounted them in my newer 
MacOS 10.6 machine.  This makes the resource fork visible to mac-savvy 
programs, such as Apple's QuickTime Player.  I used the current QuickTime 
Player to open the old movie file, and to save it to a new file.  It is 
the files save from QuickTime Player that I have been trying to transcode 
to other formats.  The file Problem1.mov mentioned above is an example of 
a file saved by the current QuickTime Player.

Thanks,
Mike



From:   Carl Eugen Hoyos <cehoyos at ag.or.at>
To:     mencoder-users at mplayerhq.hu
Date:   02/28/2012 07:38 AM
Subject:        Re: [MEncoder-users] Questions about fps and synch for 
vintage QuickTime movies
Sent by:        mencoder-users-bounces at mplayerhq.hu



Mike Spreitzer <mspreitz <at> us.ibm.com> writes:

> I used a stopwatch to time the playback time between two events 
> in the movie (it is short), and got the same amount (33 seconds) 
> in each of those four cases. 

(FFmpeg will tell you the number of frames, so you will easily find out 
the actual fps, but see below.)

> Why are these two pieces of software making different claims about FPS?
> 
> When I try to transcode, using mencode, the sound and video get out of 
> sync.

Did you test ffmpeg -i input -qscale 2 out.avi ?
If that also produces out-of-sync files, please provide a sample.
I believe it is unlikely that the problem you see is in any way 
related to fps.

Please do not cross-post, it is considered very rude, Carl Eugen

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