[Libav-user] Field order

[Hendrik Leppkes]

On Mon, May 18, 2015 at 1:17 PM, Nisar Ahmed <nisar.med at gmail.com> wrote:
> While decoding, libav is producing a different field order for some movies
> which is resulting in interlacing artefacts on the output screen. I tried
> finding field order information inside AVCodecContext->field_order and
> AVFrame->top_field_first but both values are always set to AV_FIELD_BT and 0
> respectively.
>
> I need to know which field order then file will decode with so that I can
> make conversion or can I ask libav to do that.
>

AVFrame->top_field_first is what you want to look at. If its not set,
then the video stream in question may simply not have any field order
information.

- Hendrik