output bitrate changes on progressive/interlaced mixed stream

[Alex_Y_]

Hello,

I'm trying to transcode some interlaced video (PicStruct = FIELD_TFF) which sometimes becomes progressive for a couple of seconds (PicStruct = PROGRESSIVE | FIELD_TFF). At the moment of picture struct change (FIELD_TFF changes to PROGRESSIVE | FIELD_TFF) the encoder output bitrate changes to ~0.5x of target bitrate. And if the encoder was initialized at PROGRESSIVE | FIELD_TFF fragment, the bitrate goes upto 2x of target bitrate when the picture struct changes to FIELD_TFF. The issue appears at H264 encoder on High Profile only.

For now as a workaround I'm just closing the encoder after an SPS change and initializing it again. Is it expected behaviour of the h264 HW HP encoder or am I missed something?

I'm using slightly modified sample_multi_transcode example, Ivy bridge, 9.18.10.3165 driver, win7 x64, media sdk 2013R2

[Alex_Y_]

attaching sdk tracer log for more details


 

[Nina_K_Intel]

Hi Alex,

Thank you for reporting the issue and getting the tracer log, we will investigate and get back to you. Would it be possible to additionally share the stream with picture structure change? (e.g. via ftp.intel.com)

Thanks,

Nina

[Alex_Y_]

Hi Nina,

Thank you for the prompt reply. The file name is pub/incoming/out_cut.ts
 

[Nina_K_Intel]

Hi Alex,

I'm sorry - files are stored on ftp for only 24 hours and I didn't expect you'd upload so fast on Friday :) Could you please reupload?

Thanks much,

Nina

[Alex_Y_]

Hi Nina,

no problem, file name is the same - pub/incoming/out_cut.ts
 

[Nina_K_Intel]

Thanks Alex, I got the file.

Nina