December 2023 - ffmpeg-user - lists.ffmpeg.org

ffmpeg and use of the ildct flag in progressive encoding
by Nik Armstrong 18 Dec '23

18 Dec '23

I've encountered a scenario where someone else has programmed an ffmpeg encoding command with flags that seem puzzling, and I'm having difficulty understanding their purpose. The command in question is: ffmpeg -loglevel info -y -r 29.97 -start_number 0 -i image_sequence_%4d.png -vcodec dnxhd -vf format=yuv422p10,colorspace=bt709:iall=bt601-6-625:fast=1 -b:v 220M -flags +ildct output.mov I've been struggling to find information on what the addition of ildct does to the output. It appears to be influencing the media to perceive it as interlaced, even though it is, in fact, progressive. Using the flag ildct seems counterintuitive and unproductive.

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MXF file using mpeg2video in a windows environment
by 大石脩斗 18 Dec '23

18 Dec '23

Dear ffmpeg support I'm Oishi from KNB. I'm trying to combine mxf file, wav file, and image files using ffmpeg. I'm using the Windows command prompt. Is it possible to use the codec mpeg2Video in a Windows environment? Do I need to install anything additional to use it? I'll post the code I'm currently creating as an attachment. I would like to meet the following conditions. Please let me know if there is anything I can do ・Video Format:Mpeg Video GOP:15 Bitrate:50M ・Audio Format:PCM Number of channel:8(channel 3 to 8 are silent, 1channel is stored in 8stream) Sample rate:48KHz Bit depth:24bit I hope I can hear from you soon Best regards --------------------------------------------------- Shuto Oishi Kitanihon Broadcasting Co., Ltd.

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Re: [FFmpeg-user] FFmpeg's H264 and HEVC QSV encoder wrappers not obeying the set GOP size parameter value via -g:v
by Dennis Mungai 17 Dec '23

17 Dec '23

On Mon, 18 Dec 2023 at 00:55, Dennis Mungai <dmngaie(a)gmail.com> wrote: > Hello there, > > As tested with FFmpeg 6.1 and git tip master, FFmpeg's H.264 and HEVC QSV > encoder wrappers, ie h264_qsv and hevc_qsv are not accepting the configured > GOP size(s) set via the generic option -g:v. > > A trivial command such as the one shows below demonstrates the failure: > > ffmpeg -thread_queue_size 5120 -nostdin -y -fflags +genpts -y \ > -init_hw_device vaapi=va:/dev/dri/renderD129 \ > -init_hw_device qsv=qs@va \ > -filter_hw_device qs \ > -extra_hw_frames 64 \ > -threads:v 2 -async 1 \ > -probesize 10M -analyzeduration 10M \ > -f mpegts -fix_teletext_pts 1 -scan_all_pmts 1 -merge_pmt_versions 1 \ > -i "input.ts" \ > -vf 'hwmap=derive_device=qsv,format=qsv,vpp_qsv=deinterlace=2:scale_mode=0:async_depth=4' \ > -sc_threshold 0 -strict -1 -bitrate_limit:v 0 -g:v 50 -async_depth:v 4 -look_ahead_depth:v 40 \ > -preset:v medium -refs:v 5 -extbrc:v 1 -bf:v 0 -low_power:v 1 -r:v 25 \ > -b:v 4500k -minrate:v 4500k -maxrate:v 4500k -bufsize:v 9000k -rc_init_occupancy:v 4500k -c:v h264_qsv \ > -c:a aac -ac 2 -b:a 128k \ > -flags -global_header+cgop -max_muxing_queue_size 2048 -max_interleave_delta 0 -flush_packets 0 -fps_mode cfr -f mpegts \ > -y "out.ts" > > > And when the output is analyzed with ffprobe via: > > ffprobe -select_streams v -show_entries frame=pict_type,pts_time -of csv=p=0 -skip_frame nokey -i filter.ts > Iframes.txt > > > The GOP distance is clearly set to 10, instead of the specified value of 2: > > less Iframes.txt > 2.981333,I > 13.221333,I > 23.461333,I > 33.701333,I > 43.941333,I > 54.181333,I > 64.421333,I > 74.661333,I > 84.901333,I > 95.141333,I > 105.381333,I > 115.621333,I > 125.861333,I > 136.101333,I > 146.341333,I > 156.581333,I > 166.821333,I > > > I'll attach the sample file below demonstrating the anomalous GOP size > issue after encoding. > Copying in Xiang and Artem. > > Warm regards, > > Dennis. > Hello there, I fixed it. The root cause of this anomaly is due to the external bit rate control mode in use (-extbrc 1) which also enables mini-GOPs and scenecut detection. Both of these options can be disabled by passing -adaptive_i 1 -adaptive_b 1

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Multiple overlays at specific times
by emmanuel martin 16 Dec '23

16 Dec '23

I have two inputs that are the same image. The first one, I loop to create a video for 8 seconds. I also create two streams that I will overlay. The background is the normal video, and above it is the same video with a LUT (Look-Up Table) that I applied earlier. I make the top video appear as an overlay with a fade-in effect that lasts x seconds before reaching 100%. To create a 'flash' effect, I want to overlay instances of my base image (participant1.jpg) at different very close intervals. The first overlay displays, but not this one "[out][1]overlay=enable='between(t,3.25,3.26)'[outv]", and I can't figure out the reason. Have I made a mistake somewhere? Thank you very much for your valuable advice :) ffmpeg -loop 1 -i participant1.jpg -i participant1.jpg -filter_complex "\ [0]split=2[v1][v2];\ [v2]format=rgba,lut3d='red.cube'[v3];\ [v3]fade=in:st=0.25:d=2.93:alpha=1[ov];\ [v1][ov]overlay[bg];\ [bg][1]overlay=enable='between(t,3.20,3.21)'[out];\ [out][1]overlay=enable='between(t,3.25,3.26)'[outv]"\ -map "[outv]" -c:v libx264 -t 8 -pix_fmt yuv420p output.mp4

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Strip all formatted entries from an ssa or srt stream
by bbb 16 Dec '23

16 Dec '23

Hi, I'm still improving my automatically added fallback subtitle stream. My TV doesn't cope well with formatted or positioned entries. They just result in a bunch of numbers and codes that fill the entire screen so that no meaningful part of the subtitles is visible any more. All those subtitle creators who mean well by translating signs in place or trying to sync the colour of some song lyrics are making it a pain for me to watch those subtitles on my TV. I would like to be able to strip all formatted or positioned parts of the subtitles, so that only the speech translations remain. I already have an idea how to approach that, but I thought maybe somebody already come up with a solution that I can use or adapt. Kind regards, Nils

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Generate "log.txt" of files with warning messages when normalizing LUFS
by CMG DiGiTaL 16 Dec '23

16 Dec '23

Hi, I'm using ffmpeg normalize loundnorm and some audios show "innacurete" or "1152 samples" warning messages. What I wanted to know is if there is a command that I can use to generate a "log.txt" of only the files with alert messages, for my control? Thank's Claudio.

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Re: [FFmpeg-user] How do I prevent this FFmpeg from removing the Exif metadata?
by Dave F 14 Dec '23

14 Dec '23

Please don't send replies just to the sender. I wish to use ffmpeg. Unless someone can categorically say 'ffmpeg can't do that' I'd like to search for an answer in thif ffmpeg forum. I've tried ImageMagick with various command combinations. None come anywhere as near as that ffmpeg command in terms of clarity & file size reduction. The most annoying thing is when viewing the resulting images (I use both freecommander & irfanview) the scroll wheel to zoom in/out becomes much more sensitive & I have to click the wheel many more times to zoom in the equivalent amount. DaveF On 13/12/2023 23:42, Carl Zwanzig wrote: > (offlist) > On 12/12/2023 12:27 PM, Dave F via ffmpeg-user wrote: >> How do I prevent this FFmpeg from removing the EXIF metadata? >> It|'s a single frame image||.| >> >> |ffmpeg -i "Input.JPG" -vf scale=iw*.5:-1 -update true "Output.jpg"| > > For image files, you may find that ImageMagick and it's "-resize" > option is a better tool for the job (start with > https://imagemagick.org/script/convert.php and look at the examples). > > z! >

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How do I prevent this FFmpeg from removing the Exif metadata?
by Dave F 12 Dec '23

12 Dec '23

Hi How do I prevent this FFmpeg from removing the EXIF metadata? It|'s a single frame image||.| |ffmpeg -i "Input.JPG" -vf scale=iw*.5:-1 -update true "Output.jpg"| I tried combinations of |-movflags use_metadata_tags| and |-map_metadata 0| but with no success. Maybe I'm not implementing the command correctly? Thanks in advance DaveF

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Question about libopus encoding.
by Aditya Dandavate 07 Dec '23

07 Dec '23

*cap_soundcommand* "ffmpeg -f s16le -ar %s -ac 2 -i - -c:a libopus -vbr on -compression_level 0 -application lowdelay -b:a 128k -y temp_a.nut" Is this VBR encoding, is `-b:a 128k` the average bitrate or maximum/minimum allowed bitrate ?

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ReplayGain Not Working Correctly
by Annie Body 05 Dec '23

05 Dec '23

HiI am using ffmpeg version 26.06.2023 with a third party PC music streamer MinimServer.They use ffmpeg to configure and stream music via an ethernet connection between my PC and HiFi streamer. I have found an issue where ffmpeg is not working as expected: stream.transcodemp3:wav24, flac:wav24; stream options convOut=-af volume=replaygain=track applies replaygain to MP3 and Flac does not apply replaygain+ only replaygain- MinmServer have confirmed the settings are as expected and infer there is an issue with ffmpeg. Would you please advise if the settings are correct for streaming replaygain settings and whether replaygain- is working in ffmpeg.regards

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