VBR MPEG-4 and VBR AAC with different values

[Adithya]

Hi guys i need your help and it's urgent

I've been trying to encode a video with this command

ffmpeg.exe -i Input.mp4 -strict -experimental -acodec aac -ab 40k -vcodec mpeg4 -s 320x240 -b:v 400k -minrate 0k -maxrate 600k -bufsize 4096k -r 23.976 output.3gp

But i want the audio to be between 40k and 64k but the video output is like this

Video
ID                                       : 1
Format                                   : MPEG-4 Visual
Format profile                           : Simple@L1
Format settings, BVOP                    : No
Format settings, QPel                    : No
Format settings, GMC                     : No warppoints
Format settings, Matrix                  : Default (H.263)
Codec ID                                 : 20
Duration                                 : 1h 2mn
Bit rate mode                            : Variable
Bit rate                                 : 400 Kbps
Maximum bit rate                         : 600 Kbps
Width                                    : 320 pixels
Height                                   : 240 pixels
Display aspect ratio                     : 16:9
Original display aspect ratio            : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.217
Stream size                              : 177 MiB (90%)
Writing library                          : Lavc55.58.102
Language                                 : English

Audio
ID                                       : 2
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 1h 2mn
Duration_LastFrame                       : -9ms
Bit rate mode                            : Variable
Bit rate                                 : 40.0 Kbps
Maximum bit rate                         : 600 Kbps
Channel count                            : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Stream size                              : 17.7 MiB (9%)

How can i change the output audio bitrate?

If i try to encode both separately and mux it, it's showing constant bitrate for the video and audio.

Thanks in advance

[Baldrick]

WHy do you need it to be vbr 40k-64k? Problem with standalone player?

[pandy]

https://trac.ffmpeg.org/wiki/Encode/AAC

[Adithya]

Actually i am ok even if its constant audio but how can i have a different bitrate than the video?

If i use -b:v 400k -minrate 0k -maxrate 600k it is also used in the audio,i just want it to be in the video file

[Adithya]

Bump

[pandy]

try to group video bitrate and audio bitrate, if not then probably you need split signal chain trough -map and do this as separate instances https://trac.ffmpeg.org/wiki/How%20to%20use%20-map%20option

[Adithya]

Sorry but i don't understand can you please tell me how to use it in my case?

[poisondeathray]

-minrate:v 0k -maxrate:v 600k

[Adithya]

-minrate:v 0k -maxrate:v 600k

Thankyou