[FFmpeg-user] ffmpeg output list question

[Carl Eugen Hoyos]

Am Mo., 16. Dez. 2019 um 09:03 Uhr schrieb Mark Filipak
<markfilipak.windows+ffmpeg at gmail.com>:
>
> On 12/15/2019 06:58 PM, Carl Eugen Hoyos wrote:
> > Am So., 15. Dez. 2019 um 22:20 Uhr schrieb Mark Filipak
> > <markfilipak.windows+ffmpeg at gmail.com>:
> >>
> >> On 12/15/2019 02:38 PM, Carl Eugen Hoyos wrote:
> >>> Am So., 15. Dez. 2019 um 16:50 Uhr schrieb Mark Filipak
> >
> >>> FFmpeg (and digital transcoders in general) doesn't know about fields,
> >>> it can only work with frames. (This is also related to the specifications
> >>> of sane video codecs.)
> >>
> >> If ffmpeg doesn't know about fields, how can it decode interlaced content?
> >
> > The mentioned specifications require that conforming decoders output
> > frames...
>
> Carl, that's the most important information I've received to date. It
> changes most of all my research -- mostly, it simplifies things. Thank
> you very, very much.

> I knew that ffmpeg encoders output solely frames, but I assumed that,

I may misunderstand but this is at least misleading, could be considered
wrong.

> when an interlaced container was encountered, ffmpeg decoders (hence
> HandBrake) worked with fields.

The FFmpeg infrastructure cannot work with fields which is the reason that
interlaced encodings of hevc and jpeg2000 are not supported correctly.

> Due to the German in your messages, I assume you're in Europe. My
> research needs some PAL VOB samples of the following:

> - Vintage "PAL" Cinematic Source -- Purely 24 FPS content (no VBR) in an
> 25 FPS container (that plays at 25 Hz with 4% speedup).

Just search for a a pal vob file of a movie.

> - "PAL" Cinematic Source -- 25 FPS source (25th frame repeat) in a 25
> FPS container (I currently have only 1 modern "PAL" movie sample).

I consider this broken, FFmpeg can (at least theoretically) fix such streams.

> - PAL TV Source -- 25 FPS sequential fields (from PAL TV).

Any pal transport stream, they of course exist both with interlaced and
progressive content, always interlaced encoding.

> - Mixed PAL Source -- PAL TV show with embedded movie clips (e.g., some
> "Making of" documentaries).
> - Vintage Mixed PAL Source -- Vintage PAL TV show (4% speedup) with
> embedded movie clips (e.g., some "Making of" documentaries).

Not sure about these, but they were mentioned here before.

I wonder in which category true vfr movies like the Titanic intro fall...

Generally, I don't think it is correct to argue that increasing frame rate
helps encoding, it depends on the specific input.

Carl Eugen