Constant frame rate is converted to variable ?

[Vangelis Christodoulou]

Hi,

When using Subler to add metadata info to mp4 files (video and audio passthrou) I noticed the resulting m4v files have a variable frame rate while the original frame rate is constant (as per usual). Any ideas why? Here is the mediainfo report:

Original: Video ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L4.1 Format settings : CABAC / 4 Ref Frames Format settings, CABAC : Yes Format settings, ReFrames : 4 frames Codec ID : V_MPEG4/ISO/AVC Duration : 1 h 26 min Bit rate : 3 997 kb/s Width : 1 920 pixels Height : 1 080 pixels Display aspect ratio : 16:9 Frame rate mode : Constant Frame rate : 23.976 (24000/1001) FPS Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.080 Stream size : 2.41 GiB (86%) Writing library : x264 core 148 r2762+1 5eb0fa5 Encoding settings : cabac=1 / ref=3 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=18 / lookahead_threads=3 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=1 / weightp=2 / keyint=240 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00 Default : Yes Forced : No Color range : Limited Color primaries : BT.709 Transfer characteristics : BT.709 Matrix coefficients : BT.709

And after tagging in Subler: Video #1 ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L4.1 Format settings : CABAC / 4 Ref Frames Format settings, CABAC : Yes Format settings, ReFrames : 4 frames Codec ID : avc1 Codec ID/Info : Advanced Video Coding Duration : 1 h 26 min Bit rate : 3 997 kb/s Width : 1 920 pixels Height : 1 080 pixels Display aspect ratio : 16:9 Frame rate mode : Variable Frame rate : 23.976 (23976/1000) FPS Minimum frame rate : 5.988 FPS Maximum frame rate : 23.981 FPS Original frame rate : 23.976 (24000/1001) FPS Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.080 Stream size : 2.41 GiB (86%) Writing library : x264 core 148 r2762+1 5eb0fa5 Encoding settings : cabac=1 / ref=3 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=18 / lookahead_threads=3 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=1 / weightp=2 / keyint=240 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=20.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00 Language : English Encoded date : UTC 2017-12-23 12:13:15 Tagged date : UTC 2017-12-23 12:13:24 Color range : Limited Color primaries : BT.709 Transfer characteristics : BT.709 Matrix coefficients : BT.709 Menus : 3,4