[Cin] Anamorphic 16:9 SD-DV(D) widescreen to AV1.webm

[Terje J. Hanssen]

Den 12.01.2024 09:40, skrev Andrea paz:
>> Also, pixel aspect ratio (PAR) is also known as sample aspect ratio (abbreviated SAR) in some industrial standards (such as H.264[2]) and output of programs (such as ffmpeg
>> Note 3: "ffprobe shows PAR as SAR". ffmpeg.org. Retrieved 2022-06-10.
> Yes, exactly. That is what confuses me.
> The theory is simple: DAR = PAR x SAR
> DAR and SAR are "frame aspect ratio," PAR is "pixel aspect ratio." It
> can be said that when SAR (let's imagine it as Width x Height pixels,
> although it can be expressed as a ratio) is different from DAR we have
> an anamorphic video and on the Compositor we see the deformed image.
> Then we intervene with PAR which enlarges or shrinks the pixel so that
> SAR is equal to DAR again.
> A possible first confusion is that SAR and DAR can be expressed as
> both Width x Height and aspect ratio. Another thing that can be
> confusing is that SAR is not about the Set Format window, but only
> about the Resource --> Assett --> Info --> Resize, or also Timeline
> --> RMB --> Resize Track or, further, the Scale plugin).
>
> I don't quite understand why ffmpeg and CinGG confuse the definitions
> of PAR and SAR. Maybe for simplicity of code? In fact, the CinGG
> workflow is not difficult: we choose the project properties, including
> the frame size with the "Aspect ratio" option of the Set Format window
> (which is tied to Width x Height). Then, depending on the sources, we
> can change W and H, using W Ratio and H Ratio to perform the
> calculations automatically. All without the need to recall the
> concepts of SAR, PAR and DAR. If we then consider that anamorphic
> pixels affect only a very small minority of cases, not putting the
> concept of PAR serves to consider W/H Ratio as just a simple
> multiplicative factor between the initial and project frame sizes.
>
> Does this explanation sound correct to you? I would appreciate your
> opinions, because I would like to change the manual.

I have not much to add, but I think it would be useful to add a table 
with the actual
DAR, SAR (and PAR?) values for the most common anamorphic video formats 
similar
https://en.wikipedia.org/wiki/Pixel_aspect_ratio#Pixel_aspect_ratios_of_common_video_formats

And  what and when is manual input necessary in Cinelerra Set Format 
beyoind Preset
and possibly also in the Project setting?