[FFmpeg-user] an issue on decoding a mxf xavc long gop file.

Carl Eugen Hoyos ceffmpeg at gmail.com
Mon Apr 8 00:37:46 EEST 2019

2019-04-05 17:03 GMT+02:00, Yufei He <yhe at matrox.com>:
> On 04/05/2019 09:44 AM, Carl Eugen Hoyos wrote:
> 2019-04-04 20:06 GMT+02:00, Yufei He
> <yhe at matrox.com><mailto:yhe at matrox.com>:
> Hi
> I'm trying to trancode a 1080i xavc long gop mxf file with my
> codec, the file's frame rate is 29.97.
> In my decoder, avctx->framerate.den is 1001, avctx->framerate.num
> is 15000.
> This is wrong.
> I tested the following:
> $ ffmpeg -i m2641080i30m25.xavc.mxf -qscale 2 -vcodec mpeg4 out.mov
> The output file plays both audio and video for 3:53 secondes (+/- 0:01).
> This seems correct to me, no?
> Carl Eugen
> Hi Carl
> Yes, it works without using my codec.
> But it has error on debugging with my codec.
> [cid:part1.1295D7D8.8D499E95 at matrox.com]

Please fix your quoting and please do not attach
screen-shots, there may be exceptions but a
large debug window probably never is.

> I use avctx->framerate in my codec.


I am not claiming that there is no bug (I opened a ticket)
but I don't see why you need the value, even more so
if there is not issue with the native decoder.

> From the picture above, you can see framerate->num
> is 15000, framerate->den is 1001. framerate->num
> should be 30000.

If you already know what the issue is, I suggest you
send a patch (made with git format-patch, sent to
ffmpeg-devel) to fix it.

Sorry, Carl Eugen

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