[FFmpeg-devel] [Uncompressed MP4] RFC - Draft Encoder

[Devon Sookhoo]

With this patch, I can generate an uncompressed mp4 without specifying the
-c:v rawvideo option:

$ ffmpeg  -i input.mp4  -c:v rawvideo  -pix_fmt rgb24  output.mp4

Originally, it was failing the mux.c validate_codec_tag() function and
never reached mov_get_rawvideo_codec_tag(). I found the following
init_muxer() comment useful:
                // the current rawvideo encoding system ends up setting
                // the wrong codec_tag for avi/mov, we override it here

On Wed, Oct 16, 2024 at 4:11 AM Tomas Härdin <git at haerdin.se> wrote:

> Have a look at mov_get_rawvideo_codec_tag()
>
> /Tomas
>
> tis 2024-10-15 klockan 08:17 -0600 skrev Devon Sookhoo:
> > This updated patch registers the 'uncv' tag in the isom_tags.c
> > ff_codec_movvideo_tags[] list. However, I still need to specify the
> > tag
> > with the "-tag:v uncv" option. I hoped this change would set 'uncv'
> > as the
> > default tag for raw mp4 video, but I'm not sure what the issue is.
> >
> > I'm also looking into passing FATE and adding additional test cases
> > to
> > cover this new code. The documentation is helpful, but there's still
> > a
> > steep learning curve to get all this put together.
> >
> > Any help would be greatly appreciated.
> >
> > On Sat, Oct 12, 2024 at 1:59 AM Tomas Härdin <git at haerdin.se> wrote:
> >
> > > ons 2024-10-09 klockan 20:08 -0600 skrev Devon Sookhoo:
> > > > Sounds good, I'll look into adding rawvideo to the list of
> > > > movcodec_tags.
> > > >
> > > > Looking at the AVPixFmtDescriptor, I noticed:
> > > > AVComponentDescriptor
> > > > comp[4]; Does this line limit the component count to only four?
> > > > Encoding
> > > > video with many components is an important use case.
> > >
> > > I am aware of no pixel format with more than 4 components so
> > > probably.
> > > I've never seen hyperspectral imagery used in this project. I've
> > > worked
> > > with it before though
> > >
> > > > Complex pixels are used in applications that involve both
> > > > amplitude
> > > > and
> > > > phase information, particularly in signal processing and imaging
> > > > techniques
> > > > where the Fourier transform is frequently applied. Examples
> > > > include
> > > > Synthetic Aperture Radar (SAR), MRI scans, and radio astronomy.
> > >
> > > Yep, suspected as much
> > >
> > > /Tomas
> > > _______________________________________________
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> > >
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