[Ffmpeg-devel] dv ntsc 640x480 sqare pixels probed as 720x480

[herve.flores]

Le 23 mai 06 ? 11:55, Marcus Engene a ?crit :

> Hi,
>
> If I export a clip in Premiere 1.5 as
> DV/DVCPRO - NTSC
> 640x480
> Square pixels

this format doesn't exist
DV NTSC is non-square px, size is 720*480

>
> ffmpeg probes this as 720x480

because it's its real size
try mpegstreamclip (if you're on macos or windows)
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> Why does it do that? Is there any way to tell is something is  
> square pixels instead of 0.9?

tell ffmpeg -i input -s 640x480 ...
(but it's a BIG error with all interlaced streams)

> Quicktime player reports the clip to be 640x480

a .mov is a container, a .mov has 2 informations for display:
- a display size
- a "natural" display size for the container
your example has the 2 sizes to 640*480

but the track inside your mov is 720*480
ffmpeg is right

then you can force display size of the container(or track) but not  
contents/real size of the track
(if you want to see by your own the real size, use the API quicktime  
or QTKit.framework for Mac or Windows)


> example:
> http://www.engene.se/640asp1.mov  (~750kB)
>
> Best regards,
> Marcus
>
> $ ffmpeg -v 2 -i 640asp1.mov
> FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
>  configuration:  --enable-gpl --enable-mp3lame --enable-xvid -- 
> enable-shared --disable-mmx --enable-amr_nb --enable-amr_wb --extra- 
> cflags=-fPIC --enable-faad --enable-faac --enable-x264
>  libavutil version: 49.0.0
>  libavcodec version: 51.4.0
>  libavformat version: 50.2.1
>  built on Feb 12 2006 12:15:36, gcc: 3.4.3 20041212 (Red Hat  
> 3.4.3-9.EL4)
> Input #0, mov,mp4,m4a,3gp,3g2, from '640asp1.mov':
>  Duration: 00:00:00.2, start: 0.000000, bitrate: 28842 kb/s
>  Stream #0.0(eng), 100/2997, 29.97 fps(r): Video: dvvideo, yuv411p,  
> 720x480, 100/2997
> Must supply at least one output file

bye

Herv?