TMS320DM368: Relation of H.264enc intra, IDR, GDR interval & gdrduration parameters

OK I've updated to the latest encoder (02.30.00.06, we were using 02.30.00.04) and rebuilt, no change to the error condition.

As soon as GDRduration > idrFrameInterval the encoder stops with Extended Error: 41028/0xA044 IH264VENC_ERR_GDRDURATION.

Here's our VE settings (from alg_vidEnc.c):

Input W/H 1080/1920

TargetBitRate 8000000

captureWidth 1920

targ/ref Framerate 30000 / 30000

profileIdc=66

levelIdc=42

.intraFrameInterval=0

_h264.idrFrameInterval=30

enableVUIparams=4

rateControlPreset=5

Log2MaxFrameNumMinus4=5

ConstraintSetFlag=0

entropyMode=0

transform8x8FlagIntraFrame=0

transform8x8FlagInterFrame=0

enableVUIparams=4

meAlgo=0

seqScalingFlag=0

enableARM926Tcm=0

enableDDRbuff=0

EnableLongTermFrame=0

outputDataMode=1

sliceMode=0

sliceFormat=1

encodingPreset=2

encodingPreset=XDM_HIGH_SPEED

encQuality=3

numTemporalLayers=0

svcSyntaxEnable=0

.forceFrame=3

sliceSize = (1080/16)*100/100

_h264.sliceSize=67

_h264.airRate=0

_h264.intraFrameQP=28

_h264.interPFrameQP=28

_h264.initQ=28

_h264.rcQMax=51

_h264.rcQMin=51

_h264.rcQMaxI=42

_h264.rcQMinI=1

_h264.maxDelay=2000

_h264.aspectRatioX=1

_h264.aspectRatioY=1

_h264.lfDisableIdc=0

_h264.enableBufSEI=1

_h264.enablePicTimSEI=1

_h264.perceptualRC=1

_h264.mvSADoutFlag=0

_h264.resetHDVICPeveryFrame=0

_h264.enableROI=1

_h264.metaDataGenerateConsume=0

_h264.interlaceRefMode=0

_h264.enableGDR=2

_h264.GDRduration=31

_h264.GDRinterval=269

_h264.LongTermRefreshInterval=0

_h264.UseLongTermFrame=0

_h264.SetLongTermFrame=0

_h264.maxBitrateCVBR=12000000

_h264.maxHighCmpxIntCVBR=0

_h264.CVBRsensitivity=0

_h264.CVBRminbitrate=0

_h264.LBRmaxpicsize=50

_h264.LBRminpicsize=0

_h264.LBRskipcontrol=0x50004

_h264.disableMVDCostFactor=0

_h264.rcAlgo=1

Prashanth Kumar15 said:

When you use GDR, I/IDE frame interval will be always 0(zero). Only 1st Frame will be I/IDR frame.

Can you clarify this statement: Are you saying the I/IDR Interval MUST BE SET TO 0, or are you saying that enabling GDR has the effect of setting them to 0?

The H.264 Encoder userguide makes no mention of this.

Hi,

Can you share the encoded stream?

The SPS is sent from the encoder at every GDRinterval, but PPS is not. You can try to store the SPS,PPS- NAL(only IDR frame) at your frame work, and send it at GDRintervals. For now lets keep enableGDR = 1. 

It looks like the issue may lie in the Appro IPNC code, it seems to rely on having an I/IDR frame to lock a GOP and start streaming. For whatever reason, when I/IDR==0 it does not get an initial I/IDR frame despite what the encoder manual says.

If I/IDR == 0 or >200 the Appro chain fails to lock a GOP, regardless of GDR setting. For the time being I don't think we can do much about this so we'll just have to limit the user's settings to avoid problems.

As a follow-up to this, we see I & IDR frames out of sync even if we set I=IDR=30 for example we can see sometimes the stream will be something like:

I-P-P-P-IDR-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-I-P-P-P-IDR-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P...

Is this expected behaviour or have we configured something wrong? Would forcing an I/IDR at encoder start force it to sync up?

Hi,

Fridgefreezer said:

As a follow-up to this, we see I & IDR frames out of sync even if we set I=IDR=30 for example we can see sometimes the stream will be something like:

I-P-P-P-IDR-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-I-P-P-P-IDR-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P-P...

Is this expected behaviour or have we configured something wrong? Would forcing an I/IDR at encoder start force it to sync up?

This is not the expected behaviour!. When I=IDR you should not see I. IDR overrides I. Can you run the same settings by disabling GDR(enableGDR=0)? And share your observation.

Prashanth,

I think we have identified the cause: If you have I==IDR and START / RESTART the streaming then they are in sync.

If you modify the dynamic parameters (I, IDR, framerate, maybe some others) then it can fall out of sync. Restarting streaming gets it back.

Hi,

Great to know you have route caused the issue. Thanks for closing this thread.

Thanks for your help!