[FFmpeg-user] backtrack parameters from existing file

Scott Goldman scottg at emailhosting.com
Sat Jan 5 03:59:47 CET 2013

Its a pain.. I am trying to match the output and quality of our existing
Rhozet trans-coded files.   These files were built with the following
Rhozet profile parameters:

Frame size:1280x720
level: 5.1
Multiplexer:Mpeg-4 System
Aspect Ratio:16x9
Frame Rate [Fps] 29.969999
Video bit rate mode:VBR
1 Pass
Video Bit rate 3000kbps
Max Bit rate 8000kbps
vbv buffer-size 0
entropy coding mode CABAC
# of slices per picture 1
HRD Conformance Yes
Write Timestamps Yes
Write Access Unit Delimiters Yes
GOP Size 15 frames
Min GOP Size 1 frame
Enable Scene Change Detection
IDR Frequency 1
Reference Frames 2
Number of b-pictures 2
Use Adaptive B-Frame placement Yes
Black Normalization Level 16
Grain Optimization Strength 50
Use Deblocking Y
Chroma offset 1
Colour Description Auto
Search Shape 8x8
Motion Estimation Subpixel Mode - Quarter Pixel
use fast inter/intra decisions yes
rate distortion optimization yes
fast rate distortion optimization yes
I-pictures use 16x16 intra macroblock prediction yes
I-pictures use 8x8 intra macroblock prediction yes
I-pictures use 4x4 intra macroblock prediction yes
p- and b-pictures use 16x16 intra macroblock prediction
p- and b-pictures use 8x8 intra macroblock prediction
p- and b-pictures use 4x4 intra macroblock prediction

Audio Program Type MEPG-2 AAC-LC
Channel Config:stereo
Bitrate 48kbps
sample rate 22.050
sample width 16

With so many parameters, i was hoping to give ffmpeg an existing file
and ask it to provide the right switches to transcode into the same
format with the same quality/codecs/etc.

any help is appreciated


On Fri, 2013-01-04 at 16:40 -0900, Lou wrote:
> On Fri, 4 Jan 2013 19:26:27 -0600 (CST)
> "Scott Goldman" <scottg at emailhosting.com> wrote:
> > Greetings,
> > Is there anyway that ffmpeg can look at an existing video file and provide
> > the switches used to create that fiile - or at worst case, provide
> > switches to create similar output?
> > 
> > We are trying to use ffmpeg to transcode to mp4 and need to match
> > quality/bitrate/etc of an existing file as close as possible.
> > 
> > Thanks in advance
> > Scott
> It depends on the format and the encoder. Using the same bitrate to
> attempt to achieve a similar quality is usually a waste of time (and/or
> bits). Not all encoders are equal in terms of how many bits are required
> to reach a certain (subjective) quality.
> "mp4" is a container format that can utilize several video and audio
> formats. You'll need to be more specific as to what you need exactly.
> If you tell us what you're doing and what you're trying to achieve we
> can try to provide examples suited for your needs.
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