[FFmpeg-user] gain the highest quality with H264 at a certain bit rate

[negin tebyani]

this is the source video mediainfo:

General
Complete name                            : arsenalVScristalPalas.mp4
Format                                   : MPEG-4
Format profile                           : JVT
Codec ID                                 : avc1 (avc1/mp42)
File size                                : 347 MiB
Duration                                 : 11mn 1s
Overall bit rate mode                    : Constant
Overall bit rate                         : 4 407 Kbps
Encoded date                             : UTC 2017-01-03 09:36:38
Tagged date                              : UTC 2017-01-03 09:36:38

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High at L3.2
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 2 frames
Format settings, GOP                     : M=3, N=30
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 11mn 1s
Bit rate mode                            : Constant
Bit rate                                 : 4 000 Kbps
Width                                    : 1 280 pixels
Height                                   : 720 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 50.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.087
Stream size                              : 315 MiB (91%)
Language                                 : English
Encoded date                             : UTC 2017-01-03 09:36:38
Tagged date                              : UTC 2017-01-03 09:36:38

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 11mn 1s
Source duration                          : 11mn 1s
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Frame rate                               : 46.875 fps (1024 spf)
Compression mode                         : Lossy
Stream size                              : 30.3 MiB (9%)
Source stream size                       : 30.3 MiB (9%)
Language                                 : English
Encoded date                             : UTC 2017-01-03 09:36:38
Tagged date                              : UTC 2017-01-03 09:36:38


and yes, I need to use constant bitrate. do I need to use 2 pass with
constant bitrate?