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Patrick Cooper

Panasonic G6 progressive / interlaced video query

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Ive been using a Panasonic G6 for the last few years. For full HD video recording, Ive always used 25p in AVCHD (or so I thought.) In the menu option within the AVCHD setting, it says: "1920 x 1080 50i, image sensor output 25p, 24mbps."

 

Here we have a bit of a contradiction – it indicates both interlaced and progressive with this particular menu option. Obviously, it can't be both. Ive had the assumption that this meant that the camera is recording interlaced video but converting it to progressive for the output. Though Ive no idea whether I'm right or wrong about this.

 

Tonight, I imported one of these supposed 25p AVCHD videos into Shotcut NLE software. To my surprise, when I checked the properties of the clip within Shotcut, it indicated that the video was interlaced. That had me puzzled. All this time, I thought I was producing progressive video with this camera when I used that setting.

 

As a test, to see if Shotcut was reading info accurately, I imported some Panasonic G2 footage which records 1280 x 720p video. And sure enough, the properties tab indicates that the video from the G2 is progressive.

 

There is also another 25p option in the Panasonic G6 in the MP4 setting. This particular option reads as follows: "1920 x 1080 25p, image sensor output 25p, 20mbps." No mention of interlaced video there. Which would be the better option to use? I want the best quality with progressive video. I'll be submitting quite a few clips to stock footage agencies and some of these companies don't accept interlaced video. Even if the AVCHD option is interlaced, I could always convert it to progressive within Shotcut. Ive previously output such clips as progressive with Sony Movie Studio and didn't see any issues with motion artifacts. I also note that the AVCHD option has a higher bitrate compared to the MP4 25p option which is a bonus. Actually, I have accumulated a fair number of AVCHD clips already that I want to submit to these stock agencies.

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Panasonic (and most of the Japanese cameras) make up their own standards that fit the ASIC's (mpeg encoders) inside the camera.

 

So yes 50i would be interlaced, 25p would be progressive. "Sensor output" probably refers to the video output, not the capture medium.

 

Hope that makes sense.

 

Also, be careful with using 25p for stock companies. Only broadcast uses 25fps, it's far easier to use 24 (23.98) or 30 (29.97) when shooting because those two standards are what most people will be using in post production, even in Europe if not going to broadcast.

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Thankyou for the info. I didn't realise that 25fps is not used much outside of broadcast. Is that the same for Australia and Hong Kong? However, I guess it's easier to convert 25fps to 30fps than the other way around. Some folks who shoot stock say that frame rates aren't much of an issue because clients can convert it to their needs. Though I'm not sure if there are some clients who are very fussy about a particular frame rate for their project.

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25p is still very much the norm for 50Hz countries .. broadcast for not.. nearly all the work I get from UK/Singapore/HK/Europe is 25p.. there is no advantage to shoot 29.97p for post production in Europe ,not sure where that came from ?? .. 29.97p seems to be the dying frame rate if anything..very rarely requested these days.. even from the US ..its nearly always 23.98p..

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25p is still very much the norm for 50Hz countries .. broadcast for not.. nearly all the work I get from UK/Singapore/HK/Europe is 25p.. there is no advantage to shoot 29.97p for post production in Europe ,not sure where that came from ?? .. 29.97p seems to be the dying frame rate if anything..very rarely requested these days.. even from the US ..its nearly always 23.98p..

It's impossible to convert 25p to 29.97 without motion blur issues. It's very easy to convert 29.97 to 25 or 24 without motion blur, simply alter the flags of the file and bam, you've got the frame rate you need.

 

I do a lot of editing with stock footage and nearly everyone shoots 25p and it's very annoying since nearly all of my shows are 23.98 or 29.97. For the 29.97 shows, it's impossible to use the 25p footage.

 

Ohh and yes, 29.97 is still the most widely used frame rate in the world because it translates well to 59.94 which is the broadcast standard in non-pal countries.

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You'll have to forgive me as I'm not great with numbers (and maths has never been my strong point.) I assumed that 25fps would be just as ideal as 24fps because both frame rates are very close to each other. And considering that for decades, movies have been shot at 24fps, I haven't heard of any serious complaints when these films are released in the NTSC format for the American home video market. So just to clarify, converting 24ps fps to 29.97 fps won't have the same issues as 25?

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Posted (edited)
On 3/1/2019 at 12:33 PM, Tyler Purcell said:

It's impossible to convert 25p to 29.97 without motion blur issues. It's very easy to convert 29.97 to 25 or 24 without motion blur, simply alter the flags of the file and bam, you've got the frame rate you need.

 

I do a lot of editing with stock footage and nearly everyone shoots 25p and it's very annoying since nearly all of my shows are 23.98 or 29.97. For the 29.97 shows, it's impossible to use the 25p footage.

 

Ohh and yes, 29.97 is still the most widely used frame rate in the world because it translates well to 59.94 which is the broadcast standard in non-pal countries.

Tyler.. there are only  a hand full of countries that use 60 Hz.. look it up.. India/China/Europe, Asia except Korea,Japan has both.. all PAL .. 95% or more of the world population live in 50Hz locations.. Only the US and few small Islands are 60hz..  .. its a tiny minority .most widely used frame rate in the world.. ??. 30p is not a global standard at all.. if anything 23.98p is becoming one..easy for 50Hz and 60Hz.. yes no one wants to deal with 30p.. except local news and sports in there US..  non NSTC countries is basically the whole planet ..

Edited by Robin R Probyn
spelling

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NTSC /PAL are analog broadcast terms anyway.. but Hz wise .. Secam is also a 50 fields /25frame based system too.. . 60Hz is massively in the minority globally ..land size and population wise..  29.97 is patently not the "most widely used frame rate in the world"..   even though its used in America.. weird  as that may seem 🙂 ..  all the Natgeo /Discovery shoots I do, which will all air in the US.. 23.98p..   

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Robin, I think you may not understand what I'm talking about. We're referring to stock footage only here, not broadcast, not sync-sound material, just those filler shots that you can't afford to get for whatever reason. The goal of having stock footage online is to "sell" said stock footage. So if your footage doesn't fit the specs properly, then you won't sell it.

If you have a 23.98, 24, or 25fps clip, it's impossible to use it in a 29.97, 30, 59.94 or 60fps environment without adding cadence to the file. This makes it look bad, especially from 25 to 29.97 which is the most common conversion. 

If you have a 30 fps clip, you can very easily make it work for 29.97, 59.94 and 60fps. Plus with a very simple header flag change on the file, you can make it playback at whatever FPS you want LOWER then 30fps. So if you have a 25fps sequence, you can easily get 30fps media to work, all be it at a slightly slower frame rate. This generally isn't an issue for stock footage, as it's very easy to manipulate frame rate in the NLE system and add frame blending instead of cadence. 

If I were to sell stock footage, I would shoot everything in 4k and at either 30fps or 60fps so that no matter what, it's convertible to any other media standard. 

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