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mpeg2 standard, framerate, movie plays to slow ...

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tombert

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DLNA master

Posts: 217

Joined: Wed Oct 13, 2010 8:01 pm

Post Sat Nov 20, 2010 6:27 pm

mpeg2 standard, framerate, movie plays to slow ...

Hi there,

I experienced a funny thing: played an avi movie with 23.976 framerate, the movie is exactly 44"6' long but it plays on my TV till 55". My TV by the way is Sony KDL-EX series.

So I tested:
ffmpeg -threads 2 -i battle1_ori.avi -y -vcodec mpeg2video -b 8000k -maxrate 8000k -bufsize 5097k -r 25 -g 15 -copyts -acodec ac3 -ab 192k -sn -f mpegts battle_test.mpeg
This file plays till 44"3' - just better.

And tested again by using AVS4You Video Converter - converted avi to avi by changing the framerate to 25.
This file plays exactly till 44"6.

It also looks more accurate when doing fast-forward/backward. And - this is a wild guess - maybe some TVs may have problems when the timestamps and the actual movie progress differs to much. I'am refering especially to:
viewtopic.php?f=5&t=1029

Then I checked here:
http://de.wikipedia.org/wiki/MPEG-2
which tells me that standard mpeg2 has 30 fps only? ... but thats not the point ... or my TV simply only accepts integers as fps :D

Anyhow ... before putting a feature request having the possibility to customize the framerate for each profile I would like your opinion.
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zip

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Serviio developer / Site Admin

Posts: 17212

Joined: Sat Oct 24, 2009 12:24 pm

Location: London, UK

Post Sun Nov 21, 2010 11:41 am

Re: mpeg2 standard, framerate, movie plays to slow ...

whato does ffmpeg -i says?
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tombert

User avatar

DLNA master

Posts: 217

Joined: Wed Oct 13, 2010 8:01 pm

Post Sun Nov 21, 2010 11:51 am

Re: mpeg2 standard, framerate, movie plays to slow ...

The original:
[mpeg4 @ 0x9fd1680]Invalid and inefficient vfw-avi packed B frames detected
Input #0, avi, from 'battle1_ori.avi':
Metadata:
ISFT : Nandub v1.0rc2
Duration: 00:44:06.89, start: 0.000000, bitrate: 1105 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 640x352 [PAR 1:1 DAR 20:11], 23.98 tbr, 23.98 tbn, 23.98 tbc
Stream #0.1: Audio: mp3, 48000 Hz, 2 channels, s16, 128 kb/s


The file I converted with AVS4You:
Input #0, avi, from 'battle1_framerate25_avi.avi':
Duration: 00:44:06.88, start: 0.000000, bitrate: 1090 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 640x352 [PAR 1:1 DAR 20:11], 25 tbr, 25 tbn, 25 tbc
Stream #0.1: Audio: mp3, 44100 Hz, 2 channels, s16, 128 kb/s



The file I converted with ffmpeg:
[mpegts @ 0x930e420]max_analyze_duration reached
Input #0, mpegts, from 'battle1_framerate25_ffmpeg.mpeg':
Duration: 00:44:06.84, start: 1.400000, bitrate: 2196 kb/s
Program 1 Service01
Metadata:
name : Service01
provider_name : FFmpeg
Stream #0.0[0x100]: Video: mpeg2video, yuv420p, 640x352 [PAR 1:1 DAR 20:11], 8000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
Stream #0.1[0x101]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s

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