xHe-AAC: ffprobe marks all the frames as KEY frame

[Thierry]

xHE-AAC seems to have a notion of key frame, called IPF.

however, when running ffprobe on a xHE-AAC bitstream, all the frames are marked as K. However, should we not mark only the IPF frame as K?

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/usr/local/15s_sine.mp4':
  Metadata:
    major_brand     : dash
    minor_version   : 0
    compatible_brands: iso6mp41
    creation_time   : 2024-10-29T22:35:41.000000Z
  Duration: 00:00:15.00, start: 0.000000, bitrate: 67 kb/s
  Stream #0:0[0x1](und): Audio: aac (xHE-AAC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 66 kb/s (default)
    Metadata:
      creation_time   : 2024-10-29T22:35:41.000000Z
      vendor_id       : [0][0][0][0]
packet|codec_type=audio|stream_index=0|pts=0|pts_time=0.000000|dts=0|dts_time=0.000000|duration=N/A|duration_time=N/A|size=1129|pos=1680|flags=K__
packet|codec_type=audio|stream_index=0|pts=2048|pts_time=0.046440|dts=2048|dts_time=0.046440|duration=N/A|duration_time=N/A|size=350|pos=2809|flags=K__
packet|codec_type=audio|stream_index=0|pts=4096|pts_time=0.092880|dts=4096|dts_time=0.092880|duration=N/A|duration_time=N/A|size=367|pos=3159|flags=K__
packet|codec_type=audio|stream_index=0|pts=6144|pts_time=0.139320|dts=6144|dts_time=0.139320|duration=N/A|duration_time=N/A|size=371|pos=3526|flags=K__
packet|codec_type=audio|stream_index=0|pts=8192|pts_time=0.185760|dts=8192|dts_time=0.185760|duration=N/A|duration_time=N/A|size=372|pos=3897|flags=K__
packet|codec_type=audio|stream_index=0|pts=10240|pts_time=0.232200|dts=10240|dts_time=0.232200|duration=N/A|duration_time=N/A|size=378|pos=4269|flags=K__
packet|codec_type=audio|stream_index=0|pts=12288|pts_time=0.278639|dts=12288|dts_time=0.278639|duration=N/A|duration_time=N/A|size=366|pos=4647|flags=K__

Also, one other problem is that we describe the codec AAC as AV_CODEC_PROP_INTRA_ONLY, which seems to be incorrect with xHE-AAC.

[Thierry]

Fragment Mp4 file with xHE-AAC codec and IPF at the beginning of each fragment