How to get the output resolution after successful encode? - ffmpeg

Question

I'm using fluent-ffmpeg and I'm already able to get the output resolution in the 'on end' event:
createFfmpegCommand()
.input(fs.createReadStream(readPath))
.noAudio()
.fps(30)
.format('mp4')
.videoCodec('libx264')
.videoFilter([
{filter: 'scale', options: '1920:1920:force_original_aspect_ratio=decrease'},
{filter: 'setpts', options: '1.5*PTS'},
])
.outputOption('-crf 30')
.outputOption('-movflags frag_keyframe')
.outputOption('-movflags +faststart')
.output(mp4WriteStream)
.on('start', () => console.log('processing started'))
.on('error', err => console.error('err', err))
.on('end', (_,res) => console.log('processing success',res))
.run();
However, i'd like it to be machine-readable (json or xml). Instead, it looks like this:
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with Apple clang version 12.0.0 (clang-1200.0.32.28)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_8 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'pipe:0':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42mp41
creation_time : 2020-05-28T09:51:18.000000Z
Duration: 00:00:02.23, start: 0.000000, bitrate: N/A
Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 9108 kb/s, 30 fps, 30 tbr, 30k tbn, 60 tbc (default)
Metadata:
creation_time : 2020-05-28T09:51:18.000000Z
handler_name : ?Mainconcept Video Media Handler
encoder : AVC Coding
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
[libx264 # 0x7f92d9808e00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 # 0x7f92d9808e00] profile High, level 4.0, 4:2:0, 8-bit
[libx264 # 0x7f92d9808e00] 264 - core 161 r3027 4121277 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 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=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=30.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'pipe:1':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42mp41
encoder : Lavf58.45.100
Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
Metadata:
creation_time : 2020-05-28T09:51:18.000000Z
handler_name : ?Mainconcept Video Media Handler
encoder : Lavc58.91.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame= 64 fps=0.0 q=36.0 size= 0kB time=00:00:00.16 bitrate= 1.7kbits/s dup=21 drop=0 speed=0.316x
frame= 100 fps=0.0 q=-1.0 Lsize= 108kB time=00:00:03.23 bitrate= 274.7kbits/s dup=33 drop=0 speed=3.25x
video:106kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.906519%
[libx264 # 0x7f92d9808e00] frame I:1 Avg QP:25.71 size: 8782
[libx264 # 0x7f92d9808e00] frame P:25 Avg QP:30.10 size: 2308
[libx264 # 0x7f92d9808e00] frame B:74 Avg QP:27.92 size: 564
[libx264 # 0x7f92d9808e00] consecutive B-frames: 1.0% 0.0% 3.0% 96.0%
[libx264 # 0x7f92d9808e00] mb I I16..4: 19.4% 77.2% 3.3%
[libx264 # 0x7f92d9808e00] mb P I16..4: 0.3% 0.8% 0.1% P16..4: 4.6% 1.3% 0.4% 0.0% 0.0% skip:92.5%
[libx264 # 0x7f92d9808e00] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 4.0% 0.2% 0.0% direct: 0.0% skip:95.7% L0:44.2% L1:54.8% BI: 1.0%
[libx264 # 0x7f92d9808e00] 8x8 transform intra:75.0% inter:78.3%
[libx264 # 0x7f92d9808e00] coded y,uvDC,uvAC intra: 8.8% 8.8% 2.4% inter: 0.3% 0.2% 0.0%
[libx264 # 0x7f92d9808e00] i16 v,h,dc,p: 77% 7% 10% 6%
[libx264 # 0x7f92d9808e00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 48% 3% 42% 1% 1% 1% 1% 1% 1%
[libx264 # 0x7f92d9808e00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 28% 16% 26% 7% 4% 4% 3% 5% 6%
[libx264 # 0x7f92d9808e00] i8c dc,h,v,p: 89% 5% 5% 1%
[libx264 # 0x7f92d9808e00] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 # 0x7f92d9808e00] ref P L0: 66.9% 11.1% 16.7% 5.3%
[libx264 # 0x7f92d9808e00] ref B L0: 87.5% 9.9% 2.6%
[libx264 # 0x7f92d9808e00] ref B L1: 96.4% 3.6%
[libx264 # 0x7f92d9808e00] kb/s:259.80
Which doesn't let me be comfortable that my regex to extract the output resolution is always going to work.
Also, I don't wanna make another call/fileread just to get the resolution. Mainly because my files are stored in S3, where ffprobe doesn't work.