Game / screen capture, OBS, variable frame rate import and Lightworks - USE OBS STUDIO! Posted by jmoore2-12 Feb :25

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1 Game / screen capture, OBS, variable frame rate import and Lightworks - Posted by jmoore2-12 Feb :25 Hello all, I have been struggling to get Lightworks editing anything produced from OBS in the last few days. Gamers who record are going to be fairly reliant on OBS or similar due to NVENC or VCE on their GPUs to get a good quality capture with minimum overhead. Small issue with this is that the variable frame rate captures you get from a lot of these programs do not work properly in Lightworks when transcoded or linked in directly when imported. This usually leads to an external transcode having to be done for each file which is s total pain in the bum. Luckily the new OBS Studio which appears to can record in a FIXED FPS. Lightworks hasn't seemed to struggle at all with these files and I have been able to edit / cut with no issues after transcoding AND LINKED. tl;dr Use OBS Studio when recording your screens or in games to avoid Lightworks A: breaking or B: wasting time and quality via additional any transcoding. My working settings : Please note: The Keyframe interval must be set to 1 in order for linked editing to work properly. 1 / 17

2 Forum mods/ Admins you may wish to pin this post / pin a USE OBS STUDIO IF SCREEN CAPTURING post. Posted by donkpow - 13 Feb :33 That would indicate the problem is not in the container format. You will have to do a transcode. That involves decoding and encoding to the new file. If ffmpeg can fix the error, it will. Posted by jmoore2-13 Feb :44 donkpow wrote: That would indicate the problem is not in the container format. You will have to do a transcode. That involves decoding and encoding to the new file. If ffmpeg can fix the error, it will. Handbrake has managed to encode beyond 4 minutes and 50 seconds no problem, this said I have managed to edit the file in Lightworks by linking in the file rather than transcoding it. Linking in wasn't working before as I was having issues due to CrossFireX, I think! Either way I have my full file now. Just to confirm, the OBS Studio recording does show a constant FPS so I think I have proved you wrong donkpow wrote: Please prove me wrong. 2 / 17

3 Which is awesome, since in theory OBS Studio should have far less issues with editing as it is not VFR? Many thanks for the help! Posted by donkpow - 13 Feb :05 Just to confirm, the OBS Studio recording does show a constant FPS so I think I have proved you wrong. That you have, sir. One of the files was CFR, the other was not. A word of caution. I am still not convinced all computers will produce a CFR source from OBS Studio. If you command OBSS to CFR but the computer is not up to the task, will it still produce a file that is CFR? Or, will it produce a file that is VFR but says it is CFR in MediaInfo? Posted by jmoore2-13 Feb :12 All very good questions! I can't easily test that. I will add however, that this encoding has been done using VCE on my GPU so other people using OBS to record using a non VCE method (i.e. CPU) with CFR may get something different. I will test this now using x264 on the CPU instead. Posted by jmoore2-13 Feb :18 3 / 17

4 jmoore2 wrote: All very good questions! I can't easily test that. I will add however, that this encoding has been done using VCE on my GPU so other people using OBS to record using a non VCE method (i.e. CPU) with CFR may get something different. I will test this now using x264 on the CPU instead. FYI: There is an option to enable variable frame rate in the options I am leaving unticked (obviously.) OBS Studio using Standard Mode CBR "faster" x264 "main" CPU encoding shows the following: Mediainfo: General Complete name : F:Video Work Areaffmpeg git win64-staticbin _ mp4 : MPEG-4 : Base Media Codec ID : isom (isom/iso2/avc1/mp41) File size : 114 MiB : 2mn 58s Overall bit rate : Kbps Writing application : Lavf Video ID : 1 : AVC /Info : Advanced Video Codec : Main@L4.2 settings, CABAC : Yes settings, ReFrames : 4 frames Codec ID : avc1 Codec ID/Info : Advanced Video Coding : 2mn 58s : Kbps Width : pixels 4 / 17

5 Height : pixels Display aspect ratio : 16:9 mode : fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : Stream size : 107 MiB (94%) Writing library : x264 core 148 r Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=12 / lookahead_threads=4 / 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=1 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=10 / rc=cbr / mbtree=1 / bitrate=5000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=5000 / vbv_bufsize=5000 / nal_hrd=none / filler=1 / ip_ratio=1.40 / aq=1:1.00 Audio #1 ID : 2 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 2mn 58s mode : 164 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) Compression mode : Lossy Stream size : 3.49 MiB (3%) Title : Track1 Default : Yes Alternate group : 1 Audio #2 ID : 3 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 2mn 58s mode : 164 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) 5 / 17

6 Compression mode : Lossy Stream size : 3.49 MiB (3%) Title : Track2 Default : No Alternate group : 1 Processed FFProbe file below: [STREAM] index=0 codec_name=h264 codec_long_name=h.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 profile=main codec_type=video codec_time_base=1/120 codec_tag_string=avc1 codec_tag=0x width=1920 height=1080 coded_width=1920 coded_height=1088 has_b_frames=2 sample_aspect_ratio=0:1 display_aspect_ratio=0:1 pix_fmt=yuv420p level=42 color_range=n/a color_space=unknown color_transfer=unknown color_primaries=unknown chroma_location=left timecode=n/a refs=4 is_avc=true nal_length_size=4 id=n/a r_frame_rate=60/1 avg_frame_rate=60/1 time_base=1/15360 start_pts=507 start_time= duration_ts= duration= bit_rate= max_bit_rate=n/a bits_per_raw_sample=8 nb_frames= / 17

7 nb_read_frames=10728 nb_read_packets=n/a DISPOSITION:default=1 DISPOSITION:dub=0 DISPOSITION:original=0 DISPOSITION:comment=0 DISPOSITION:lyrics=0 DISPOSITION:karaoke=0 DISPOSITION:forced=0 DISPOSITION:hearing_impaired=0 DISPOSITION:visual_impaired=0 DISPOSITION:clean_effects=0 DISPOSITION:attached_pic=0 TAG:language=und TAG:handler_name=VideoHandler [/STREAM] Both FFProbe and mediainfo indicate constant frame rate. Would seem to indicate CBR is giving CFR under GPU and CPU encoding then! Posted by donkpow - 13 Feb :25 I agree. I tried the NVENC on my system. Basically unloading encode of the capture to the video card. Presets. The uncompressed H.264 NVENC encode had errors so I reverted to cpu encoding. I haven't gotten around to trying the new version. Development stopped on OBS when the effort switched to the multi-platform version. I'll get around to it one of these days. Posted by jmoore2-13 Feb :37 Just wanted to check if overloading would cause a drop to VFR, short answer is no! 7 / 17

8 Overloaded the CPU with the "slower" mode, video is effectively frozen with a few small sections actually playing. FYI: There is an option to enable variable frame rate in the options I am leaving unticked (obviously.) OBS Studio using CBR Standard Mode "slower" x264 "main" CPU encoding shows the following: Mediainfo: General Complete name : F:Video Work Areaffmpeg git win64-staticbin _ mp4 : MPEG-4 : Base Media Codec ID : isom (isom/iso2/avc1/mp41) File size : 40.1 MiB : 1mn 3s Overall bit rate : Kbps Writing application : Lavf Video ID : 1 : AVC /Info : Advanced Video Codec : Main@L5 settings, CABAC : Yes settings, ReFrames : 8 frames Codec ID : avc1 Codec ID/Info : Advanced Video Coding : 1mn 3s : Kbps Width : pixels Height : pixels Display aspect ratio : 16:9 mode : fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : Stream size : 37.5 MiB (94%) Writing library : x264 core 148 r / 17

9 Encoding settings : cabac=1 / ref=8 / deblock=1:0:0 / analyse=0x1:0x131 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=cbr / mbtree=1 / bitrate=5000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=5000 / vbv_bufsize=5000 / nal_hrd=none / filler=1 / ip_ratio=1.40 / aq=1:1.00 Audio #1 ID : 2 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 1mn 2s mode : 163 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) Compression mode : Lossy Stream size : 1.22 MiB (3%) Title : Track1 Default : Yes Alternate group : 1 Audio #2 ID : 3 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 1mn 2s mode : 163 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) Compression mode : Lossy Stream size : 1.22 MiB (3%) Title : Track2 Default : No Alternate group : 1 Processed FFProbe file below: 9 / 17

10 [STREAM] index=0 codec_name=h264 codec_long_name=h.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 profile=main codec_type=video codec_time_base=1/120 codec_tag_string=avc1 codec_tag=0x width=1920 height=1080 coded_width=1920 coded_height=1088 has_b_frames=2 sample_aspect_ratio=0:1 display_aspect_ratio=0:1 pix_fmt=yuv420p level=50 color_range=n/a color_space=unknown color_transfer=unknown color_primaries=unknown chroma_location=left timecode=n/a refs=8 is_avc=true nal_length_size=4 id=n/a r_frame_rate=60/1 avg_frame_rate=60/1 time_base=1/15360 start_pts=507 start_time= duration_ts= duration= bit_rate= max_bit_rate=n/a bits_per_raw_sample=8 nb_frames=3780 nb_read_frames=3780 nb_read_packets=n/a DISPOSITION:default=1 DISPOSITION:dub=0 DISPOSITION:original=0 DISPOSITION:comment=0 DISPOSITION:lyrics=0 DISPOSITION:karaoke=0 DISPOSITION:forced=0 DISPOSITION:hearing_impaired=0 DISPOSITION:visual_impaired=0 DISPOSITION:clean_effects=0 DISPOSITION:attached_pic=0 10 / 17

11 TAG:language=und TAG:handler_name=VideoHandler [/STREAM] Both FFProbe and mediainfo indicate constant frame rate. Would seem to indicate CBR is giving CFR even under very heavy overloaded CPU encoding! Posted by donkpow - 13 Feb :44 Yes, I see. So what you're saying is that frames are duplicated so that CFR can be maintained? FWIW, I don't use CBR. CBR is good for streaming. Posted by jmoore2-13 Feb :55 It certainly appears to be frame duplication to maintain CFR (I assume from watching VLC, I haven't checked frame by frame.) Either way very encouraging. I believe that OBS Studio does support NVENC and Quicksync, but I can't test either of those as I lack the equipment I am mainly focusing on CBR since typically I and others would be streaming the video to twitch and recording it at the same time. This said I am fairly confident that VBR with CFR will work very nicely (assuming it does stick to CFR.) I'm testing this now. 11 / 17

12 Posted by donkpow - 13 Feb :06 Interesting. If it is maintaining CFR, that will facilitate workflow for those that want to transcode or import directly to Lightworks. They may not appreciate the apparent stall in the stream. Many will see duplicated frames in the editor and be disappointed. So you capture in CBR, edit and export from Lightworks, and then stream? Have you checked the bitrate on the exported files? You can get bit rate data from ffprobe, too. Actually, you can get tons of information and put it in a spreadsheet. Then make a graph or whatever. I can't remember but I think you save the data in CSV format. I'll have to check that to see. Posted by jmoore2-13 Feb :17 FYI: There is an option to enable variable frame rate in the options I am leaving unticked (obviously.) OBS Studio using VBR 5000kbit Standard Mode x264 "high" GPU (VCE) encoding shows the following: Mediainfo: General Complete name Codec ID File size Overall bit rate Writing application : F:Video Work Area _ mp4 : MPEG-4 : Base Media : isom (isom/iso2/avc1/mp41) : 42.6 MiB : 1mn 5s : Kbps : Lavf / 17

13 Video ID : 1 : AVC /Info : Advanced Video Codec : High@L4 settings, CABAC : Yes settings, ReFrames : 4 frames Codec ID : avc1 Codec ID/Info : Advanced Video Coding : 1mn 5s : Kbps Width : pixels Height : pixels Display aspect ratio : 16:9 mode : fps Standard : Component Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : Stream size : 40.0 MiB (94%) Color range : Limited Audio #1 ID : 2 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 1mn 5s mode : 164 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) Compression mode : Lossy Stream size : 1.27 MiB (3%) Title : Track1 Default : Yes Alternate group : 1 Audio #2 ID : 3 : AAC /Info : Advanced Audio Codec : LC Codec ID : 40 : 1mn 5s mode 13 / 17

14 : 164 Kbps Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 KHz : fps (1024 spf) Compression mode : Lossy Stream size : 1.27 MiB (3%) Title : Track2 Default : No Alternate group : 1 Processed FFProbe file below: [STREAM] index=0 codec_name=h264 codec_long_name=h.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 profile=high codec_type=video codec_time_base=1/120 codec_tag_string=avc1 codec_tag=0x width=1920 height=1080 coded_width=1920 coded_height=1088 has_b_frames=1 sample_aspect_ratio=1:1 display_aspect_ratio=16:9 pix_fmt=yuv420p level=40 color_range=tv color_space=unknown color_transfer=unknown color_primaries=unknown chroma_location=left timecode=n/a refs=4 is_avc=true nal_length_size=4 id=n/a r_frame_rate=60/1 avg_frame_rate=60/1 time_base=1/15360 start_pts=0 start_time= / 17

15 duration_ts= duration= bit_rate= max_bit_rate=n/a bits_per_raw_sample=8 nb_frames=3904 nb_read_frames=3904 nb_read_packets=n/a DISPOSITION:default=1 DISPOSITION:dub=0 DISPOSITION:original=0 DISPOSITION:comment=0 DISPOSITION:lyrics=0 DISPOSITION:karaoke=0 DISPOSITION:forced=0 DISPOSITION:hearing_impaired=0 DISPOSITION:visual_impaired=0 DISPOSITION:clean_effects=0 DISPOSITION:attached_pic=0 TAG:language=und TAG:handler_name=VideoHandler [/STREAM] Both FFProbe and mediainfo indicate a constant frame rate with VBR, which is excellent for anyone wanting to record in high quality for minimum file size. This is a high quality encode of 1080p at 60 FPS footage (I would say near as damnit close to source) at 43 megabytes for a minute. I would upload it for people to see but it's Battlestar Galactica and copyright. Posted by jmoore2-13 Feb :23 donkpow wrote: Interesting. If it is maintaining CFR, that will facilitate workflow for those that want to transcode or import directly to Lightworks. They may not appreciate the apparent stall in the stream. Many will see duplicated frames in the editor and be disappointed. So you capture in CBR, edit and export from Lightworks, and then stream? Have you checked the bitrate on the exported files? 15 / 17

16 You can get bit rate data from ffprobe, too. Actually, you can get tons of information and put it in a spreadsheet. Then make a graph or whatever. I can't remember but I think you save the data in CSV format. I'll have to check that to see. With respect to LW import and edit, the only stall / duplicated frames you would get is if you overloaded the CPU or GPU when encoding the stream / recording. With OBS Studio, I was under the impression that recording would operate at the same settings as the stream if streaming (which is limited to 3600 kbit on twitch for example) and since streaming is almost always prefered as CBR you'd be recording in CBR by virtue of streaming in it. I don't capture first, process with lightworks, then stream. I do the above ^ stream first with OBS Studio (which should record at the same settings as the stream), then import the recorded stream, edit, re-encode then upload to youtube. Posted by donkpow - 13 Feb :28 Oh, I see. I save to file using ultrafast 30 fps, setting bitrate to whatever maximum. The file always gets transcoded before import to the editor. Normally the file needs to be conformed to fps. I have never streamed. I don't do long captures, either. Posted by jmoore2-13 Feb :38 donkpow wrote: Oh, I see. I save to file using ultrafast 30 fps, setting bitrate to whatever maximum. The file always gets transcoded before import to the editor. Normally the file needs to be conformed to fps. I have never streamed. I don't do long captures, either. 16 / 17

17 Strictly speaking, I believe its not technically impossible from stream services to take VBR but you start running into a trade off with what the say they want, what they will accept and ultimately what your networking is willing to put up with. Personally I think CBR isn't really required, I think it just makes their networking easier since it doesn't vary like VBR. Swing and roundabouts though, it means their total bandwidth usage rises. Posted by jmoore2-13 Feb :46 Additional Note: Lightworks REALLY DOES NOT LIKE VBR extremely high bitrate? files linked for editing. Highly recommend transcoding any VBR high bitrate file. It has to actively transcode the file when linked by the looks of things and is very sluggish and cannot play the file even on my rig. 17 / 17