Encoding interlaced / targeting BD5

[MadMonkey57]

Hi all,

My camcorder outputs SD PAL Video (720x576x25i) and I plan to buy an HD Camcorder that will (probably) output HD PAL Video (1920x1080x25i).
My goal is to turn these contents to Blu Ray, more specifically in a way it ensures playability on BD5s.

I realize that I've been avoiding to encode interlaced frames for a very long time and I can get away with it using well known techniques (smart-deinterlace, smart-bob, PAL slow down, 50p encodings, ...) at least with SD sources:

720x576x25i --> (Smart) Deinterlacing 720x576x25p --> Slowing down 720x576x23.976p
720x576x25i --> (Smart) Bobbing 720x576x50p --> Upscaling 1280x720x50p
... or others that include changing FPS (changefps/mflowfps in avisynth)

But for HD sources, new issues pop up:

- Much more CPU needed notably for smart deinterlacing/bobbing
- In the case of 50p encoding, downscaling is mandatory for Blu Ray

1920x1080x25i --> (Smart) Deinterlacing 1920x1080x25p --> Slowing down 1920x1080x23.976p
1920x1080x25i --> (Smart) Bobbing 1920x1080x50p --> Downscaling 1280x720x50p

Before going "trials and errors", I was wondering if some you guys have experience/feedback on encoding interlaced frames as a basis for BD5 authoring (Blu Ray with extra constraints including lower data rate, vbv stuff, ...).

My main h264 encoder is x264 (rev1376, nal-hrd patch) (My fallback encoder is Adobe Media Encoder CS4).

Thanks

[kieranrk]

Your camcorder is unlikely to have 1080 lines of true detail so bobbing nicely and downscaling to 720p50 seems ok to me.

[shon3i]

Encoding as 1080@25i with x264 is fine for me. Only thing is that interlaced automaticly disable some stuff in x264 because is not yet implemented. For VBV you should not go over 15000/15000, and then you can use 2 second GOP which in you case --keyint 50 --min-keyint 1

[lucassp]

There are some cams which capture and store the video in 1080p25 even though they are advertised as 1080i. It was already disscused here on Doom9.

[Blue_MiSfit]

MadMonkey57 is well aware of his camera's capabilities, and it does in fact record in truly interlaced mode.

I would suggest taking a look at Experssion Encoder for VC-1, and HC for MPEG-2. Compare these with x264 at equivalent bitrates for 1080i.

I'm sure x264 will beat them on a quality basis, but if you have authoring issues, these other encoders might work better.

~MiSfit

[shon3i]

but if you have authoring issuessome bad experience? I never had problems with 1080i25 interlaced x264 streams, and BD authoring (scenarist mostly) apps.

[lucassp]

Well he said there he plans to buy an HD camcoder :)

[MadMonkey57]

Your camcorder is unlikely to have 1080 lines of true detail so bobbing nicely and downscaling to 720p50 seems ok to me.
720p50 is indeed my preferred option if I definitely rule out interlaced encoding.
Encoding as 1080@25i with x264 is fine for me. Only thing is that interlaced automaticly disable some stuff in x264 because is not yet implemented. For VBV you should not go over 15000/15000, and then you can use 2 second GOP which in you case --keyint 50 --min-keyint 1
Looks like the same "logic" as progressive encoding. Last time I tried --interlaced and --vbv-xxx, I think x264 issued a warning... I'm not 100% sure though...
Isn't --min-keyint 2 the usual for progressive encoding or is --min-keyint 1 a particular setting for interlaced encoding ?
There are some cams which capture and store the video in 1080p25 even though they are advertised as 1080i. It was already disscused here on Doom9.
Could you please point me in the right direction ?
...I would suggest taking a look at Experssion Encoder for VC-1, and HC for MPEG-2. Compare these with x264 at equivalent bitrates for 1080i...~MiSfit
AFAIK VC1 and MPEG2 are not AVCHD compliant. As a matter of fact, VC1 is not even working on BD5s on my SAP (Panasonic DMP-BD35). Never checked MPEG2 but I'd rather stick with x264 in order to maximize quality and compliancy.

[moviefan]

Why not buy a 1080p camcoder? I believe they are getting more popular and available these days.

[MadMonkey57]

The thing is that I like camcorders from Sony and unfortunately they are 1080i (pro/consumers lineup). I am slowly changing mind though...:(:(:(