03-15-2013 08:35 PM - edited 03-18-2019 12:46 AM
Hi-
I'm seeing some strange behavior from my TCS', it doesnt have happen all the time and not on all boxes.
Some recordings will transcode at a much higher bitrate than others. All the aliases are set to the same template and output type, MP4/Medium.
Here are 2 recordings of the same type, trancoded on the same box. This is the media info output:
Recording 1:
General / Container Stream # 1
Total Video Streams for this File -> 1
Total Audio Streams for this File -> 1
Video Codecs Used -> AVC
Audio Codecs Used -> AAC LC
File Format -> MPEG-4
Play Time -> 1h 32mn
Total File Size -> 1.04 GiB
Total Stream BitRate -> 1 602 Kbps
Video Stream # 1
Codec (Human Name) -> AVC
Codec (FourCC) -> avc1
Codec Profile -> Baseline@L3.1
Frame Width -> 1 200 pixels
Frame Height -> 490 pixels
Frame Rate -> 29.886 fps
Total Frames -> 166430
Display Aspect Ratio -> 2.449
Scan Type -> Progressive
Colorimetry -> 4:2:0
Codec Settings (Summary) -> 1 Ref Frames
QF (like Gordian Knot) -> 0.088
Codec Settings (CABAC) -> No
Video Stream Length -> 1h 32mn 48s 739ms
Video Stream BitRate -> 1 549 Kbps
Video Stream BitRate Mode -> VBR
Bit Depth -> 24 bits
Video Stream Size -> 1.00 GiB (97%)
Date of Original Encoding -> UTC 2013-03-12 14:09:59
Audio Stream # 1
Codec -> AAC
Codec (FourCC) -> 40
Audio Stream Length -> 1h 32mn 48s 682ms
Audio Stream BitRate -> 48.0 Kbps
Audio Stream BitRate Mode -> CBR
Number of Audio Channels -> 1
Audio Channel's Positions -> C
Sampling Rate -> 48.0 KHz
Bit Depth -> 16 bits
Audio Stream Size -> 31.9 MiB (3%)
Date of Original Encoding -> UTC 2013-03-12 14:09:59
Recording 2:
General / Container Stream # 1
Total Video Streams for this File -> 1
Total Audio Streams for this File -> 1
Video Codecs Used -> AVC
Audio Codecs Used -> AAC LC
File Format -> MPEG-4
Play Time -> 1h 42mn
Total File Size -> 313 MiB
Total Stream BitRate -> 429 Kbps
Video Stream # 1
Codec (Human Name) -> AVC
Codec (FourCC) -> avc1
Codec Profile -> Baseline@L3.1
Frame Width -> 1 200 pixels
Frame Height -> 490 pixels
Frame Rate -> 29.904 fps
Total Frames -> 183080
Display Aspect Ratio -> 2.449
Scan Type -> Progressive
Colorimetry -> 4:2:0
Codec Settings (Summary) -> 1 Ref Frames
QF (like Gordian Knot) -> 0.021
Codec Settings (CABAC) -> No
Video Stream Length -> 1h 42mn 2s 220ms
Video Stream BitRate -> 375 Kbps
Video Stream BitRate Mode -> VBR
Bit Depth -> 24 bits
Video Stream Size -> 274 MiB (88%)
Date of Original Encoding -> UTC 2013-03-12 14:23:10
Audio Stream # 1
Codec -> AAC
Codec (FourCC) -> 40
Audio Stream Length -> 1h 42mn 2s 155ms
Audio Stream BitRate -> 48.0 Kbps
Audio Stream BitRate Mode -> CBR
Number of Audio Channels -> 1
Audio Channel's Positions -> C
Sampling Rate -> 48.0 KHz
Bit Depth -> 16 bits
Audio Stream Size -> 35.0 MiB (11%)
Date of Original Encoding -> UTC 2013-03-12 14:23:10
Any idea what could be causing this?
thanks
Dan
03-18-2013 06:28 AM
Hi Dan, I think the answer to your question is in the recording content itself and if there is no much animation, the final file's size after compression can be pretty small even for an 1200x490@30fps video indeed.
This is what video compression is about actually. Only the delta between two frames is stored in the file, so that explains the small size when you record a lecture for instance where the speaker doesn't move much.
Hope this makes sense,
Thomas
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