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Ariel T.

Hi,

What's the relationship among interFrameInterval, VBR/CBR mode and LOW_DELAY?

If interFrameInterval greater than 1, and in CBR mode, the encoder will cause error as follow:

[m3video] 36248:!ERROR!:ENCLINK::links_m3video/iva_enc/encLink_h264.c:[186]::INTERNAL ERROR:-1
[m3video] ALGCONTROL FAILED:CMD:1
[m3video] ERROR: XDM_UNSUPPORTEDPARAM = 14,
[m3video] ERROR: XDM_FATALERROR = 15
[m3video] ERROR: IH264ENC_UNSUPPORTED_RATECONTROLPARAMS = 21,
[m3video]
[m3video] 36249:ERR::linkID:10000024::channelID:0::errorCode:-5::FileName:links_m3video/iva_enc/encLink_h264.c::linuNum:1247::errorCondition algStatus == XDM_EOK)
[m3video] ENCLINK_H264:HEAPID:0 USED:1896
[m3video] 36249: Assertion @ Line: 813 in links_m3video/iva_enc/encLink_common.c: retVal == ENC_LINK_S_SUCCESS : failed !!!

Now, only VBR mode can set B frames interval. Is that CBR mode tied to LOW_DELAY? How can I set B frames interval in CBR mode? And our CBR mode is the ABR in fact? Can we set strict CBR in our codes? BTW, we now use RDK2.8.

Thank you very much!

Best regards,

over 12 years ago

0 Badri Narayanan over 12 years ago

TI__Guru 59700 points

B frame encoding is not supported in DVR RDK.ENabling support for B-frame encoding requires changes in encLink to handle out pf order output buffer handling which is currently not present .Also in RDK we use process APIs to encode multiple channels in a single encode call due to which B-frame encoding is not supported at codec level also.

0 Ariel T. over 12 years ago in reply to Badri Narayanan

Intellectual 825 points

How can I make changes to support B-frame encoding? You mean each channel will handle the output buffers?

0 Badri Narayanan over 12 years ago in reply to Ariel T.

TI__Guru 59700 points

Pls see this post for discussion on B-frame encoding support in RDK: http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/223281/786082.aspx#786082

As explained in the post changes to support B-frame encoding are not simple and also requires disabling processN APIs which means there will be a performance impact. As we have not tried it we cannot provide guidance also if you face hit some issues.

0 Ariel T. over 12 years ago in reply to Badri Narayanan

Intellectual 825 points

Thank you very much, Badri. And I still want to get some more details about the CBR mode. For tests, it acts more like the ABR mode. Can it be set to the strict CBR mode in DVR RDK?

0 Badri Narayanan over 12 years ago in reply to Ariel T.

TI__Guru 59700 points

Can you attach a bitstream where you see this issue of CBR target bitrate not being met.

0 Ariel T. over 12 years ago in reply to Badri Narayanan

Intellectual 825 points

The information as below:

0 Ariel T. over 12 years ago in reply to Badri Narayanan

Intellectual 825 points

The attach file.

http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/717/2061.VID_5F00_CH01.7z

0 Sayanna Chandula over 12 years ago in reply to Ariel T.

TI__Intellectual 1290 points

Hi,

CBR rate control preset is mainly applicable for video conferencing services. In such a scenario we shall not have I/IDR pictures(except 1st picture) in the encoded bit-stream. And also note that 5% bit rate deviation is expected in CBR mode.

I see intra/IDR pictures being inserted regularly in stream attached here. Try avoiding I/IDR picture insertion and observe the achieved bit rate.

Thanks.

0 Ariel T. over 12 years ago in reply to Sayanna Chandula

Intellectual 825 points

But how can I avoid I/IDR picture insertion except 1st one? Which parameter should be set?

0 1330hayacool7102 over 12 years ago in reply to Ariel T.

Guru 10655 points

hi Sayanna,

I have the same question, did you know that?

0 Badri Narayanan over 12 years ago in reply to Ariel T.

TI__Guru 59700 points

Set VENC_CHN_DYNAMIC_PARAM_S.intraFrameInterval = 0 to set only first frame in sequence to IDR frame

Processors

Processors forum

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