[x264-devel] interlace

[Nageswara Gunupudi]

Hi,
 I tried to use the --tff to encode interlace content in two passes. Surprisingly, there is about 2.84dB PSNR drop from first pass to second pass. Is it due to a possible bug in second pass encoding.  

Following are the encoding options I used in my testing.
x264.exe -v --psnr -p 1 --bitrate 1500 --keyint 250 --tff --preset slow -o out.flv in_720x480_.yuv
x264.exe -v --psnr -p 2 --bitrate 1500 --keyint 250 --tff --preset slow -o out.flv in_720x480_.yuv

Please let me know if it is known issue.

Regards,
Nag

-----Original Message-----
From: x264-devel-bounces at videolan.org [mailto:x264-devel-bounces at videolan.org] On Behalf Of Jason Garrett-Glaser
Sent: Wednesday, May 26, 2010 1:28 PM
To: Mailing list for x264 developers
Subject: Re: [x264-devel] interlace

On Wed, May 26, 2010 at 4:01 AM, Purvin Pandit <purvinp at hotmail.com> wrote:
> Hello experts,
> I have a doubt about the interlace mode support in x264.
> There were 2 parameters introduced recently: -tff/-bff. I wasnt able to
> clearly tell what the benefit of using that was over -interlace. The way I
> understand the code both are still doing field MB coding only i.e. not Paff.
> But the new flags set the picture structure correctly. What was the benefit
> realized from that? Are the field references managed separately?

TFF/BFF allows delta_poc_bottom to be set correctly, along with
appropriate pic_struct flags.

Dark Shikari
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