Inaccurate final bitrate

[yavor76]

Hello, I need some help about Xvid encoding. Everything is OK-but The problem is only with my recorded TV tuner files in MPEG-2 format. The final bitrate is different and the diversions are 30-80 %. For example: if I give a bitrate of 1700-the final bitrate is 400-1400 kbit/s .
I have no problems with any other compressions, but only with Xvid and with these files recorded with my TV tuner? I am working with Gordian Knot 0.35 rip pack and Xvid encoder (1.1 and 1.2) Encoding options: 2-pass encoding. I will post some information about mpg file and my computer configuration:

MPEG-2 file info:
MPEG-2 Validator v1.4.0.131 - 14.6.2006 г. 23:05:43

File under analysis: "D:\Records\Manual Recordings\Kanal 1_20060614215134.mpg"..!

Begin Process:

Begin Program Streams Summary:
File "D:\Records\Manual Recordings\Kanal 1_20060614215134.mpg" is a MPEG-2 Program Stream
MPEG file size 983.25 MB
MPEG Packs = 503424
Sectors delay = 0.0 ms
System headers = 1
Rate Bound = 50885200 bps -> 49692 Kbps
Video Bound = 1 active video streams
Audio Bound = 1 active audio streams
Variable Bitrate Operation (System MPEG-2 VBR)
Video Picture Rate is locked to SCR
Audio Sampling Rate is locked to SCR
MPEG Pack Size = 2048
Packets per Pack = 1
Program Mux Rate = 49692 Kbps
Total PES packets = 503426
PES Packet Lenght Max. = 2028
Number of Video Streams: 1
Number of Audio Streams: 1
Padding Stream, packets = 6, Total = 10 KB
MPEG Audio stream, ID: C0
PES packets = 26269,
Total = 51.00 MB
Video stream, ID: E0
PES packets = 477151,
Total = 920.76 MB
End Program Streams Summary.


Begin Video Streams Summary:
*Sequence_end_code NOT FOUND, in Stream E0!!
Video Delay Stream E0 = 75.3 ms
Number of Frames = 27583 -> 1103.32 Sec
Number of Sequence Headers = 1840
Sequence Headers Aligned = No
Horizontal Size = 720
Vertical Size = 576
Aspect Ratio = 4:3
Frame Rate = 25 fps
P-STD Buffer Size Bound = 224 KB (From System Header)
VBV Buffer Size = 112 -> (224 KB)
Stream Type = MPEG-2 MP@ML CBR
Chroma Format = 4:2:0
Picture Structure = Frame
Intra DC Precision = 10
Top Field First = Yes
DCT Type = Field
Quant. Scale = Linear
Scan Type = Alternate
Frame Type = Interlaced
Number of GOPs = 1840
First GOP Closed = Yes
Number of Closed GOP = 1
Max. frames per GOP (without first & last) = 15
Min. frames per GOP (without first & last) = 15
Avg. frames per GOP (Total) = 14.99
Max. Frame Size = 105824
Min. Frame Size = 10596
Average Frame Size = 34999
Frames I = 1840 -> 6%
Avg. Frame I Size = 512 KB
Frames I Total Size = 133265720 bytes, size 13%
Frames P = 7356 -> 26%
Avg. Frame P Size = 128 KB
Frames P Total Size = 402568832 bytes, size 41%
Frames B = 18388 -> 66%
Avg. Frame B Size = 51 KB
Frames B Total Size = 429556868 bytes, size 44%
Nominal bitrate (Sequence Header) = 7000000 bps -> 6835 Kbps
*Average Bitrate = 6835 Kbps
Peak Bitrate (1 sec) = 7173 Kbps
End Video Streams Summary.


Begin Audio Streams Summary:
Elementary Stream C0 is a MPEG Audio Stream
Audio Delay Stream C0 = 85.3 ms
Audio decoded bytes = 211829760 -> 1103.28 Sec
P-STD Buffer Size Bound = 4 KB (From System Header)
Found 0 sync words
Audio Sync Losses: 0
Layer = 2
bitrate = 384 Kbps
Frequency = 48000 Hz
Error protection = Disabled
Private flag = 0
Mode = stereo
Copyright flag = 0
Original flag = 0
Emphasis = none
Left Channel DC Level = -71.2 dBFS
Right Channel DC Level = -71.2 dBFS
Left Channel Peak Level = -1.6 dBFS
Right Channel Peak Level = -1.6 dBFS
*Left Channel RMS Level = -15.4 dB
*Right Channel RMS Level = -15.4 dB
Difference Left-Right RMS Level = 0.0 dB
End Audio Streams Summary.

Video Stream Duration: 1103.32 sec -> 1103:08 (secs:frames)

Duration Difference from Video to Audio = 40 msec
Initial Delay Audio to Video (PTS based) = 10 msec

Processing time: 00:02:44

Result:
Compliance Test: Fail!!

End.



PC information:
Operating System Microsoft Windows XP Professional
OS Service Pack Service Pack 2
DirectX 4.09.00.0904 (DirectX 9.0c)
Motherboard:
CPU Type AMD Athlon XP, 1833 MHz (11 x 167) 2500+
Motherboard Name EP8RDA+Pro
Motherboard Chipset nVIDIA nForce2 Ultra 400
System Memory 512 MB (PC2700 DDR SDRAM)
BIOS Type Award (02/15/05)
Display:
Video Adapter NVIDIA GeForce4 MX 440 with AGP8X (64 MB)
3D Accelerator nVIDIA GeForce4 MX 440 with AGP8X
Multimedia:
Audio Adapter nVIDIA MCP2-S - Audio Processing Unit (Dolby Digital)
Audio Adapter Realtek ALC655 @ nVIDIA MCP2-S - Audio Codec Interface


I will appraise any help, thank you!

[Teegedeck]

I'm sorry but none of this information helps determining the source of your problem. We need your XviD settings, not your system specs or data about the orignal MPEG-2 stream.

[Sharktooth]

:search: ... it's even sticky: http://forum.doom9.org/showthread.php?t=92046

[yavor76]

:thanks:
- overflow control strength: 100
- Max overflow improvement: 80
- Max overflow degradation: 80
... only 1% undersizing :) If I use overflow control strength: 20 the undersizing is 10% but 100 is good !
Excuse me !