I have a .mp4 with resolution 712x476 (~3:2) and metadata field "Display aspect ratio: 4:3", which plays as expected in any media player that respects the metadata tag and shows the output as 4:3.
After splitting the file, the media players will not scale the video as expected, but rather display the video in the resolution of the video stream.
Would it be possible to copy the metadata such that the aspect ratio is preserved after splitting?
Mediainfo of the original file:
General
Complete name : ...
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 36.5 MiB
Duration : 1 min 53 s
Overall bit rate : 2 705 kb/s
Movie name : ...
Writing application : Lavf59.8.100
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, RefFrames : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 min 53 s
Bit rate : 2 564 kb/s
Width : 712 pixels
Height : 476 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 59.940 (59940/1000) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.126
Stream size : 34.6 MiB (95%)
Writing library : x264 core 164 r3075 66a5bc1
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / 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=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=16000 / vbv_bufsize=32000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Color range : Full
Matrix coefficients : SMPTE 240M
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 1 min 53 s
Bit rate mode : Constant
Bit rate : 128 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 1.73 MiB (5%)
Default : Yes
Alternate group : 1
Mediainfo of split file:
General
Complete name : ...
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/mp42)
File size : 58.8 MiB
Duration : 2 min 35 s
Overall bit rate : 3 170 kb/s
Movie name : ...
Writing application : Lavf59.8.100
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, RefFrames : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 2 min 35 s
Bit rate : 3 031 kb/s
Width : 712 pixels
Height : 476 pixels
Display aspect ratio : 3:2
Original display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 59.940 (59940/1000) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.149
Stream size : 56.3 MiB (96%)
Writing library : x264 core 164 r3075 66a5bc1
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / 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=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=16000 / vbv_bufsize=32000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Color range : Full
Matrix coefficients : SMPTE 240M
mdhd_Duration : 155689
Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 2 min 35 s
Bit rate mode : Constant
Bit rate : 129 kb/s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.38 MiB (4%)
mdhd_Duration : 155691