[FFmpeg-devel] [PATCH 2/2] avformat/mxfenc: support XAVC long gop

Thomas Mundt tmundt75 at gmail.com
Wed Apr 10 20:42:38 EEST 2019


Hi Baptiste,

Am Mi., 10. Apr. 2019 um 00:29 Uhr schrieb Baptiste Coudurier <
baptiste.coudurier at gmail.com>:

> Hi Thomas, I hope you are doing well
>
> > On Apr 4, 2019, at 7:27 AM, Thomas Mundt <tmundt75 at gmail.com> wrote:
> >
> > Hi Baptiste,
> >
> > […]
> > For RP2027 Class 100 1080/50i I still get the error: frame size does not
> > match index unit size, 568832 != 0
> > I used the following command:
> > ffmpeg -f lavfi -i testsrc=size=1920x1080:rate=50 -vf interlace -c:v
> > libx264 -pix_fmt yuv422p10 -flags +ildct+ilme -avcintra-class 100
> > -color_primaries bt709 -color_trc bt709 -colorspace bt709 -x264-params
> >
> overscan="crop":videoformat="component":fps=25/1:interlaced=1:tff=1:force-cfr=1
> > -t 1 avci.mxf
>
> I see, that’s the switch to CBR index.
>

Works with you latest patch.


> > Also I encoded AVC High 422 Intra with the following command:
> > ffmpeg lavfi -i testsrc=size=1920x1080:rate=50 -c:v libx264 -pix_fmt
> > yuv422p -x264-params keyint=1 -t 1 avc.mxf
> > Without your patch MediaInfo shows Format profile: High 4:2:2 Intra at L4.2.
> > With your patch MediaInfo shows Format profile: High 4:2:2 at L4.2 and
> > Format_Profile_Original: High 4:2:2 Intra at L4.2.
> > According to the MediaInfo documentation, the additional
> > "Format_Profile_Original" is shown when two format profile infomations
> are
> > found that do not match.
> >
>
> Muxer uses ….32.30.01 UID which is High 422 Intra according to specs:
>
> urn:smpte:ul:060e2b34.0401010a.04010202.01323001        LEAF
> H.264/MPEG-4 AVC High 422 Intra Profile Unconstrained Coding    Identifies
> H.264/MPEG-4 AVC High 422 Intra Profile Unconstrained Coding
>
> So I’m not sure what media info is doing here.
>

I looked a little deeper into MediaInfo code. If the avc subdescriptor is
used, MediaInfo expects that in addition to profile and level, the profile
constraint is also set for intra coding.
Other MXF muxer, e.g. bmxlib, also set the profile constraint in the avc
subdescriptor.

Regards,
Thomas


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