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PAL and NTSC???

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Juan Juig
PAL and NTSC???
on May 14, 2015 at 7:04:18 pm

Hello,

just recently I have discovered a strange thing. I rendered my video with the following settings:

Custom Internet HD 1080p TEMPLATE

Frame size: HD 1080p (1920x1080)
Profile: Main
Frame rate: 25.000 (PAL)
Field order: None (progressive scan)
Pixel aspect ratio: 1.000
Number of reference frames: 1

HOWEVER even though I clearly chose the 25.000 PAL frame rate, as I open the video wih MediaInfo it says that the frame rate is 25.000 and that standard is NTSC, even though I chose Pal.

Why is that so??


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John Rofrano
Re: PAL and NTSC???
on May 15, 2015 at 3:24:39 am

[Juan Juig] "HOWEVER even though I clearly chose the 25.000 PAL frame rate, as I open the video wih MediaInfo it says that the frame rate is 25.000 and that standard is NTSC, even though I chose Pal. Why is that so??"
It might be a bug in MediaInfo. NTSC does not support 25 fps so I don't see how MediaInfo could mistaken it for NTSC unless it was a bug.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Juan Juig
Re: PAL and NTSC???
on May 15, 2015 at 3:55:54 pm

Thank you for your reply.

That's what I thought too... But media info identifies all of my 25p mp4 exported videos as NTSC standard.

And I even checked video information with MediaInfo on seperate computer with different versions of MediaInfo.

Therefore I can only assume it's a bug. Is there another probable reason for this odd thing?


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Jerome Martinez
Re: PAL and NTSC???
on May 16, 2015 at 11:19:00 am

NTSC does not support 25 fps so I don't see how MediaInfo could mistaken it for NTSC unless it was a bug.


In e.g. MPEG-2 Video, there is a bitstream field for the standard ("extension_start", "Sequence display", "video_format"), and another one for frame rate ("sequence_header", "aspect_ratio_information"). Same for AVC.

In MediaInfo, "NTSC" is displayed if:
- "video_format" bitstream field is set to "NTSC"
- width and height is 720/704 and 486/480 (there is no test on the frame rate, maybe I should add one...), impossible here (1080 lines).

Your file (its encoder) is buggy if "video_format" is set to 2 ("NTSC") instead of of 5 ("Unspecified video format") with a 1080p25 fps stream.
From specs: "video_format indicates the representation of the pictures as specified in Table E-2, before being coded in accordance with this Recommendation | International Standard. When the video_format syntax element is not present, video_format value shall be inferred to be equal to 5."

Jerome, developer of MediaInfo.


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John Rofrano
Re: PAL and NTSC???
on May 16, 2015 at 6:27:42 pm

[Jerome Martinez] " (there is no test on the frame rate, maybe I should add one...),"
I guess you have to decide if you want to trust the metadata or the stream format? If the frame rate is 50i, 50p, or 25p it's PAL regardless of what the metadata says. Since trusting the metadata (which in this case is obviously set wrong by Sony) your users assume that your program has a bug because they can clearly see it's PAL video from the frame rate.

I would recommend that frame rate overrides the metadata and reports it as PAL video.

BTW, MediaInfo is an awesome program that we recommend here a lot. Thanks for writing it.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Jerome Martinez
Re: PAL and NTSC???
on May 16, 2015 at 6:44:26 pm

I guess you have to decide if you want to trust the metadata or the stream format?


MediaInfo aims to display information from the file. there is a "video_format" field in the bistream, I display what is in that field.
I prefer to educate people that cheating on the stream: the stream is bad, complain to the company who encodes it (even if it is Sony).
I understand that people prefer to discard such issue, but I did not choose this policy.

I would recommend that frame rate overrides the metadata and reports it as PAL video.


Rely on me for never doing that ;-).
If there are incoherencies and if I implemented the detection (incoherencies detection is a hard job, very long, I priotize depending of sponsorhips), I will display both values (the metadata one and the detected one) but I'll never hide the bug from the encoder.
I consider MediaInfo as having the right output because I report the information from the bitstream. But I am thinking to split this line in 2: one for the "detected" standard, one for the "reported" standard.
I already have several coherency tests but I don't have this one, this is the main issue I see and I put it on my (long) todo-list.

BTW, MediaInfo is an awesome program that we recommend here a lot. Thanks for writing it.


:)


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John Rofrano
Re: PAL and NTSC???
on May 16, 2015 at 7:02:31 pm

[Jerome Martinez] "Rely on me for never doing that ;-)."
Too late... You are already doing that! ;-)

You said:
"In MediaInfo, "NTSC" is displayed if:
- "video_format" bitstream field is set to "NTSC"
- width and height is 720/704 and 486/480 (there is no test on the frame rate, maybe I should add one...), impossible here (1080 lines)."
So you are already guessing by looking at the width and height. If you would never do that, then there should only be one check and that is what the video_format field says. So I was just suggesting that you be more intelligent in your guessing to include frame rate with width and height since it's these three things together that determine if something is NTSC or PAL compliant.

I agree with you if the purpose of MedaiInfo is to report what it finds in the video file and not guess then it shouldn't make any inferences at all. Of course, flagging discrepancies would be a nice touch. ;-)

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Jerome Martinez
Re: PAL and NTSC???
on May 16, 2015 at 7:25:36 pm

So I was just suggesting that you be more intelligent in your guessing to include frame rate with width and height since it's these three things together that determine if something is NTSC or PAL compliant.


Implemented.
For this file, no change in MediaInfo display because "video_format" field has currently the priority (the "auto-detection" is done only if "video_format" field is missing).

If you would never do that, then there should only be one check and that is what the video_format field says.


I wanted to mean that I'll never hide the value from the "video_format" field.
There is definitely some incoherency here in MediaInfo output, and this is the reason I am thinking to split the line (1 line, 1 test).
I just don't want to hide the "video_format" field even if it is wrong. I think I'll move it to a "Reported standard" line but I need to think a bit more about it, never good to change things too quickly.

What I have in mind is to display something like:
Standard: Full HD
Reported standard: NTSC


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Juan Juig
Re: PAL and NTSC???
on May 17, 2015 at 1:03:34 pm

Thank you for all the replies. I am still confused about what is causing this.





Here are screenshots of my project and export settings.

I hope this will reveal my problem.


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John Rofrano
Re: PAL and NTSC???
on May 18, 2015 at 11:01:49 am

[Juan Juig] "I hope this will reveal my problem."
This is not your problem to solve. Sony does not supply any AVC Internet templates for PAL. Obviously, changing the frame rate to PAL doesn't change the metadata in the stream from NTSC to PAL. So this is a bug in Sony Vegas Pro. You can report it to Sony but I hight doubt it will ever get fixed. Just ignore it.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Juan Juig
Re: PAL and NTSC???
on May 18, 2015 at 8:55:57 pm

But could this bug affect anything? I mean is the video still PAL and only metadata is incorectly shown or is it actually a NTSC wanna-be video that will cause trouble if I want to import and manipulate it in programs such as Media Composer? Is this affecting video characteristics? Is the video "ruined" in any way?

I hope you know what I want to say..
And thank you so much for taking you time and replying!


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John Rofrano
Re: PAL and NTSC???
on May 18, 2015 at 10:23:44 pm

This won't affect anything negatively. It's just bad metadata. As you said, the video is still PAL and will be fine. I wouldn't worry about it since Vegas Pro has had this bug for many years and everyone who is making PAL videos for the web has been unaffected by it.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Juan Juig
Re: PAL and NTSC???
on May 18, 2015 at 10:27:52 pm

Alright, thank you so much. I found out everything I needed to know.

Thank you!


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John A. Mozzer
Re: PAL and NTSC???
on May 26, 2015 at 8:51:09 am

I have a related issue. I shot footage with my iPad, which is H.264, 1920x1080, Progressive, 30 frames per second. (Seems to me, it is neither NTSC or PAL.) I edited the footage in Final Cut Pro X, with the project's render properties set to ProRes 422 (HQ), because there seems to be no way to natively edit H.264. I created a ProRes master file using Final Cut Pro X's Share feature, because I like to use Episode for encoding to H.264. I am not changing the video properties (1920x1080, Progressive, 30 frames per second) anywhere in this workflow. MediaInfo says the resulting Episode encoded H.264 video is the PAL standard, which makes no sense to me.

It is merely an annoyance, I guess. The video seems fine. But I do wish that I could figure out where the problem is being introduced. (By Episode?)

P.S. I am using Final Cut Pro X Version 10.0.9 and Episode 6.3.1.23, outdated versions because I am keeping Snow Leopard on the particular iMac that I am using.


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Jerome Martinez
Re: PAL and NTSC???
on May 26, 2015 at 9:50:43 am

PAL standard, which makes no sense to me.


Again, I show only what the encoder says. Nothing else.
If you want a confirmation, please provide a sample file and I'll show you the "trace" of the bitstream.

The video seems fine.


Most players don't care of this bitstream field.


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John A. Mozzer
Re: PAL and NTSC???
on May 26, 2015 at 5:50:38 pm

Jerome, I am glad to know that is what MediaInfo is doing, because I didn't know before reading this thread. Yes, I would like to provide a file and see the trace.


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Jerome Martinez
Re: PAL and NTSC???
on Jun 3, 2015 at 8:14:46 pm

in your file, video_format is set to 1 (so PAL).
below is the trace of the begining of the avcC atom of your file:

0000025D AVC decode (55 bytes)
0000025D Header (8 bytes)
0000025D Size: 55 (0x00000037)
00000261 Name: avcC
00000265 Version: 1 (0x01)
00000266 Specific (46 bytes)
00000266 Profile: 100 (0x64)
00000267 Compatible profile: 0 (0x00)
00000268 Level: 40 (0x28)
0000026B Reserved: 63 (0x3F) - (6 bits)
00000269 Size of NALU length minus 1: 3 (0x03) - (2 bits)
0000026E Reserved: 7 (0x07) - (3 bits)
00000269 seq_parameter_set count: 1 (0x01) - (5 bits)
0000026B seq_parameter_set (33 bytes)
0000026B Size: 31 (0x001F)
00000272 nal_ref_idc: 3 (0x03) - (2 bits)
0000026D nal_unit_type: 7 (0x07) - (5 bits)
0000026E profile_idc: 100 (0x64)
0000026F constraints (1 bytes)
00000276 constraint_set0_flag: No
00000275 constraint_set1_flag: No
00000274 constraint_set2_flag: No
00000273 constraint_set3_flag: No
00000272 constraint_set4_flag: No
00000271 constraint_set5_flag: No
0000026F reserved_zero_2bits: 0 (0x0)
0000026F level_idc: 40 (0x28) - (8 bits)
00000276 seq_parameter_set_id: 0 (0x0)
00000276 high profile specific (18446744073709551612 bytes)
00000273 chroma_format_idc: 1 (0x1) - 4:2:0
00000272 bit_depth_luma_minus8: 0 (0x0)
00000271 bit_depth_chroma_minus8: 0 (0x0)
00000270 qpprime_y_zero_transform_bypass_flag: No
0000026F seq_scaling_matrix_present_flag: No
00000272 log2_max_frame_num_minus4: 4 (0x4)
00000271 pic_order_cnt_type: 0 (0x0)
00000274 log2_max_pic_order_cnt_lsb_minus4: 4 (0x4)
00000271 max_num_ref_frames: 2 (0x2)
00000270 gaps_in_frame_num_value_allowed_flag: No
00000273 pic_width_in_mbs_minus1: 119 (0x77)
00000276 pic_height_in_map_units_minus1: 67 (0x43)
00000275 frame_mbs_only_flag: Yes
00000274 direct_8x8_inference_flag: Yes
00000274 frame_cropping_flag (4 bytes)
00000273 frame_cropping_flag: Yes
00000272 frame_crop_left_offset: 0 (0x0)
00000271 frame_crop_right_offset: 0 (0x0)
00000270 frame_crop_top_offset: 0 (0x0)
00000273 frame_crop_bottom_offset: 4 (0x4)
00000273 vui_parameters_present_flag (22 bytes)
00000272 vui_parameters_present_flag: Yes
00000272 aspect_ratio_info_present_flag (7 bytes)
00000271 aspect_ratio_info_present_flag: Yes
00000271 aspect_ratio_idc: 1 (0x01) - (8 bits) - 1.000
00000270 overscan_info_present_flag: No
00000270 video_signal_type_present_flag (13 bytes)
0000026F video_signal_type_present_flag: Yes
00000274 video_format: 1 (0x01) - (3 bits) - PAL
00000273 video_full_range_flag: 0 (0x00) - (1 bits) - Limited
00000273 colour_description_present_flag (10 bytes)
00000272 colour_description_present_flag: Yes
00000272 colour_primaries: 1 (0x01) - (8 bits) - BT.709
00000272 transfer_characteristics: 1 (0x01) - (8 bits) - BT.709
00000272 matrix_coefficients: 1 (0x01) - (8 bits) - BT.709
00000271 chroma_loc_info_present_flag: No
00000271 timing_info_present_flag (21 bytes)
00000270 timing_info_present_flag: Yes
00000270 num_units_in_tick: 1 (0x1)
00000270 time_scale: 60 (0x3C)
0000026F fixed_frame_rate_flag: Yes
00000276 nal_hrd_parameters_present_flag: No
00000275 vcl_hrd_parameters_present_flag: No
00000274 pic_struct_present_flag: Yes
00000274 bitstream_restriction_flag (21 bytes)
00000273 bitstream_restriction_flag: Yes
00000272 motion_vectors_over_pic_boundaries_flagYes
0000026F max_bytes_per_pic_denom: 2 (0x2)
00000274 max_bits_per_mb_denom: 1 (0x1)
00000275 log2_max_mv_length_horizontal: 10 (0xA)
00000276 log2_max_mv_length_vertical: 10 (0xA)
00000273 max_num_reorder_frames: 1 (0x1)
00000270 max_dec_frame_buffering: 2 (0x2)
0000028C pic_parameter_set count: 1 (0x01)
0000028D pic_parameter_set (7 bytes)
(...)


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John A. Mozzer
Re: PAL and NTSC???
on Jun 4, 2015 at 6:09:27 pm

Thanks, Jerome. This is good to know. I'll contact Telestream's customer support to see whether they can explain why the Episoder encoder is apparently putting a video_format field set to 1 in the bitstream.


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John Rofrano
Re: PAL and NTSC???
on May 26, 2015 at 10:53:47 am

[John A. Mozzer] "I have a related issue. I shot footage with my iPad, which is H.264, 1920x1080, Progressive, 30 frames per second. (Seems to me, it is neither NTSC or PAL.)"
That's right. NTSC and PAL are "broadcast" standards. Most Internet devices (like tablets and smart phones) ignore broadcast standards and shoot whatever they want. I would say that 30 fps is closer to NTSC than PAL. But some devices use variable frame rates which give you crazy results.
[John A. Mozzer] "I edited the footage in Final Cut Pro X, with the project's render properties set to ProRes 422 (HQ), because there seems to be no way to natively edit H.264."
You can edit native H.264 if you upgrade to the latest version of FCP X.
[John A. Mozzer] "It is merely an annoyance, I guess. The video seems fine. But I do wish that I could figure out where the problem is being introduced. (By Episode?)"
It's not a problem if the video is fine. As I said, broadcast standards are often ignored for Internet video anyway. I wouldn't get hung up over them.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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John A. Mozzer
Re: PAL and NTSC???
on May 26, 2015 at 5:51:30 pm

John, thanks. Good to know that I'll be able to edit native H.264 when I upgrade to the latest version of FCP X.


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