AV_PICTURE_TYPE_NONE is returned for multiple slice H264 frames

[Gibraltar]

Summary of the bug:
An incorrect AVPictureType is returned during demux for two slice per H264 encoded streams. When calling av_read_frame to demux a packet from a Mpeg-2 H264 stream, the returned avpacket AVPictureType is AV_PICTURE_TYPE_NONE in the case where it should be AV_PICTURE_TYPE_I.
This only happens when the H264 frames has two slices per frame as shown in attached image.
How to reproduce:
Demux an H264 I frame when the H264 is two slices per frame.

[Gibraltar]

Stream that causes av_read_frame to return unknown packet type

[Carl Eugen Hoyos]

Please test current git head, please provide a sample and please explain how to reproduce.

[Gibraltar]

Sample file

[Gibraltar]

Sample added, issue appears with Git, trying to use ffmpeg.exe to reproduce.

[Gibraltar]

ffprobe errors related to iframe and missing pps/sps info.

[Gibraltar]

Using ffprobe.exe on the sample shows non-existing PPS 0 referenced even though the PPS packet with id 0 exists. Please see ffprobe screenshot.

[Carl Eugen Hoyos]

Please test current git head and please do not post screenshots, instead simply copy the console content (command line and output) into the ticket.
If the problem is reproducible with ffmpeg (the application), please provide ffmpeg command line and console output, only post ffprobe output for ffprobe-specific problems.

I am not sure I understand the overall issue: You originally reported (if I understood correctly) that ffmpeg does not recognize the frame type correctly, now you write about warnings in the console output: These warnings are normal for transport streams, you generally cannot cut such streams on (I-) frame boundaries, the warnings are produced by frames before the first keyframe.
Are you maybe searching for the showinfo filter?

[Elon Musk]

Unclear bug report.