h264 Encoder Settings ?

[bowie]

Hi,(Hopefully somone unterstands my english)

Short Question: does anybody know the correct VBV Buffersize for the STi7100 ?

More Detailed:
im trying to find useful encoder settings for a project, where i need CBR h264 SD Video muxed into mpeg2 ts.
The Videos are streamed with Live555 or Concurrent MediaHawk to STi7100 based STB

The Encoder Setup: Carbon Coder with the following Settings

Video:
PAL SD Video,
CBR 2700kbit/s, (or CBR 2500 kbit/s for AC3)
Main@3.0
GOP 50
3 B Frames
3 Reference Frames
CABAC
IDR Intervall 25/ Frequency 2

Audio:

128 kbit/s MPEG 1 Layer II or
448 kbit/s AC3

Mux:
DVB MPEG2 TS, fixed Rate 3200 kbit/s

Currently i'm hanging with 2 issues (both depending on the VBV Size ?):

1. the VBV Size:
if i set the Size to Automatic, the Encoder chooses always 9600000 bytes
after a couple of test encodings, i decided to set the buffer to 416000 bytes.
whatever i chose as VBV, after toggling from trickplay to normal play, there are blocking artefacts in the video.

The only notable Difference is the Initial CPB Removal Delay:
With VBV 9600000: ~2,0
with VBV 416000: ~0,1


2. different Overhead and decoder underflows at different VBV Size:

(the mux is always fixed at 3200 kbit/s)

1. Video 2700 kbit/s Audio 128 kbit/s Buffer 9600000 bytes produces some decoder underflows and blocking after Trickplay.

2. Video 2700 kbit/s Audio 128 kbit/s Buffer 416000 bytes
produces less decoder underflows and blocking.

3. Video 2000 kbit/s AC3 448 kbit/s Buffer 9600000 bytes produces many decoder underflows, Empty display list and blocking after Trickplay.

4. Video 2500 kbit/s AC3 448 kbit/s Buffer 416000 bytes
produces less decoder underflows and blocking.


Any help is welcome, thanks.

[Guest]

What are you using to mux to transport?

[bowie]

the internal muxer of carbon coder

[Guest]

What set-top box is it? I ask because it may have very early video drivers. I can run your streams against the very latest STi7100 video drivers if you'd like.

You can mail me at donald.graft @ st.com and we can get our field support organization involved.

[bowie]

I'm quite sure that we have new drivers, we had a h264 Bug with an older Firmware on the STB.

Since my current Testvideos are from copyrighted material, i can't provide the videos. I'm trying to encode some free samples in the next days.

Some additional tests i have done:

Playing the Videos with VLC 0.9.2:

same behaviour as on the STB

Remuxing the Videos with tsMuxeR 1.8.5(b) (only Mpeg Audio, tsMuxeR can't mux DVB compliant AC3)

Mux CBR 3200 kbit/s, 500ms up to 3000ms VBV gives VBV buffer overflow in tsmuxer
Playing the Videos on STB or with VLC:

much better performance, only on the first seconds some stuttering. With Trickplay no advancement.

[Raza]

i m new to JSVM, can any body help me to how configure encoder file? should i execute the encoder.exe from command line prompt?

thanks in advance.