Encoding Video for Blu-Ray using H264/AVC

[shon3i]

Originally Posted by mp3dom

Doesn't the pulldown already flag the stream as interlaced?

No, why should?

[mp3dom]

Because it's based on field repetition. At least, with MPEG-2 a progressive stream when a pulldown is applied, becomes interlaced with RFF.

[kieranrk]

Originally Posted by mp3dom

Because it's based on field repetition. At least, with MPEG-2 a progressive stream when a pulldown is applied, becomes interlaced with RFF.

The underlying stream is still coded progressively with soft pulldown.

Originally Posted by shon3i

EDIT: i create my own 23.976p sample, encoded using fake interlaced and puldown 32 to produce 29.97i stream, but this file will not pass mui generator.

I also tried and it seemed to pass.

[shon3i]

I also tried and it seemed to pass.

It's my mistake

[Sharktooth]

just a question... for what resolutions/frame rates combinations is --pic-struct required?

[kieranrk]

Originally Posted by Sharktooth

just a question... for what resolutions/frame rates combinations is --pic-struct required?

Anything interlaced (that includes --fake-interlaced). It can't harm to put it on anyway though.

[mp3dom]

Personally I always set pic-struct even for progressive contents as some verifiers complains about its absence.

[Sharktooth]

Thanks. One more question. If i have a 480p24 source how can i produce a blu-ray compatible stream? i mean, should i convert the framerate to 29,976? in that case how should i set the --pulldown option?

[shon3i]

you need to use pulldown with fake interlaced or interlaced

[Sharktooth]

ok, so i should set something like --pulldown 32 --fake-interlaced --pic-struct ... etc.

[shon3i]

Originally Posted by Sharktooth

ok, so i should set something like --pulldown 32 --fake-interlaced --pic-struct ... etc.

yes, but you maybe need first assume 24000/1001, because pulldown 32 on 24p source will more that 29.970fps.

[Sharktooth]

the problem is more like 24fps and 23.976 fps are usually referred as 24 fps...
so that's more a user problem than mine (i asked all those questions coz im creating megui presets for BD encoding).

[Avisynth_challenged]

Hi all,

I have a Huffyuv YV12 avi (1920x1080p @23.976fps) that I wish to encode to H.264 using x264. I'm interested in Blu-ray compliance, so looked around the forum and found this page:

http://sites.google.com/site/x264bluray/

I'm thinking of using the command line:

x264 --bitrate XXXXX --preset veryslow --tune film --weightp 0 --bframes 3 
--nal-hrd vbr --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 24 
--b-pyramid strict --slices 4 --aud --colorprim "bt709" --transfer "bt709" 
--colormatrix "bt709" --sar 1:1 --pass 1 -o out.264 input.file

I have a several questions:

1. I recall that for MPEG2 standard def encodes, a rule-of-thumb for bitrate is...
Avg: 6000 Kbps, Max: 8000 Kbps, Min: 2000 Kbps (...assuming 720x480p @23.976fps)
What rule-of-thumb bitrates are used for high-def H.264 encodes (1920x1080p @23.976fps)?

2. When encoding MPEG2 for DVD authoring, 23.976fps sources need to include pulldown flags to set the framerate to 29.97fps (soft-telecine) in NTSC-land. Does an H.264 encode need to have pulldown flags to achieve soft-telecine as well? Does the command line need to be revised to invoke pulldown?

3. MPEG2 encoders can often be configured to have the MPEG2 output be either in dropframe timecode format or non-dropframe timecode format. Does x264 have this capability available as a command line switch?

Thank you very much for your help.

[mp3dom]

1. There's no general rule for bitrate. You can go up to 40 Mbps if necessary, but you need to adhere to VBV. For 23.98p if you have a lot of space to waste, you can have an average bitrate of 35 Mbps and a max of 40 Mbps (just as example)

2. For HD sources, 23.98/24p are allowed without any soft-pulldown (this doesn't depends by h.264, but BD specs. You can have the same using MPEG2 or VC1 sources). For SD primary-video you need soft pulldown because only 50i/59.94i are allowed.

[nm]

Originally Posted by Avisynth_challenged

I have a several questions:

1. I recall that for MPEG2 standard def encodes, a rule-of-thumb for bitrate is...
Avg: 6000 Kbps, Max: 8000 Kbps, Min: 2000 Kbps (...assuming 720x480p @23.976fps)
What rule-of-thumb bitrates are used for high-def H.264 encodes (1920x1080p @23.976fps)?

I'd rather use rule-of-thumb CRF. Generally 20 is a good value to start with. If there's a need to fit the video within limited space, derive the necessary average bitrate from the allowed file size and video length.

2. When encoding MPEG2 for DVD authoring, 23.976fps sources need to include pulldown flags to set the framerate to 29.97fps (soft-telecine) in NTSC-land. Does an H.264 encode need to have pulldown flags to achieve soft-telecine as well?

Blu-ray supports straight 24000/1001 fps 1080p video without pulldown flags.

3. MPEG2 encoders can often be configured to have the MPEG2 output be either in dropframe timecode format or non-dropframe timecode format. Does x264 have this capability available as a command line switch?

Drop frame timecodes are an NTSC nuisance, not HD.

[video_magic]

Originally Posted by Avisynth_challenged

....
1. I recall that for MPEG2 standard def encodes, a rule-of-thumb for bitrate is...
Avg: 6000 Kbps, Max: 8000 Kbps, Min: 2000 Kbps (...assuming 720x480p @23.976fps)
What rule-of-thumb bitrates are used for high-def H.264 encodes (1920x1080p @23.976fps)?
....

Select a range of say, 1500 frames, from your source video (i.e. by using the trim command from avisynth in your .avs script), to use as a test to choose your bitrate but so you don't have to spend the time doing your entire video repeatedly until you find the bitrate (and other settings you might tweak and test); try and select the range from a fairly typical or even quite challenging part of your video.

I suggest for 1920x1080p , 23.976fps you try 7000 bitrate, and also do another encode at 10000 (both with exactly the same settings). Compare them with each other and with the source. Try increments of 2000 after that; but in addition to bitrate of course you could consider any other x264 settings or what you might have going on processing-wise before x264 encodes it.

[Sharc]

According to the first post in this thread the SAR for 720x576 resolution should be 16:11. My standalone (SONY 360) plays it back at 64:45 however, i.e. a picture with a SAR of 16:11 and flagged as 16:11 in the stream is slighly sqeezed on playback.
It's not a big issue, but has anyone seen a Blu-Ray standalone player which really obeys the SAR as signalled in the stream?

[kieranrk]

Originally Posted by Sharc

According to the first post in this thread the SAR for 720x576 resolution should be 16:11. My standalone (SONY 360) plays it back at 64:45 however, i.e. a picture with a SAR of 16:11 and flagged as 16:11 in the stream is slighly sqeezed on playback.
It's not a big issue, but has anyone seen a Blu-Ray standalone player which really obeys the SAR as signalled in the stream?

There is an aspect ratio flag in the HDMV extensions of the TS container that might be set wrong.

[Sharc]

Originally Posted by kieranrk

There is an aspect ratio flag in the HDMV extensions of the TS container that might be set wrong.

Ah, the container. How can I check if this flag is set? Can tsMuxer set this flag? I didn't find an option.

[A.Fenderson]

I see --mvrange 511 set on a lot of blu-ray profiles: is this strictly necessary, or does it just seem to improve compatibility on some players?