May 2026 - ffmpeg-user - lists.ffmpeg.org

Playback not Smooth
by Sheraz Ali Shah 29 May '26

29 May '26

Hi @Petro Deineka via ffmpeg-user<mailto:ffmpeg-user@ffmpeg.org> I am using FFmpeg version 7.1.1 to play an HTTPS progressive MP4 stream, but the playback is not smooth. While analyzing the MP4 boxes of the stream, I found that the audio and video sample offsets are located very far apart within the file. Note that this is a ~97 MB MP4 file. I have attached screenshots of the MP4 box structure. From my analysis: * video samples start near the beginning of the file * audio samples are located much farther away (near the end of the file) Because of this, FFmpeg keeps seeking between distant offsets during playback, which seems to cause buffering/playback issues for progressive streaming over HTTPS. Can anyone suggest a good approach to handle/play such a stream smoothly without reorganizing/remuxing the source MP4? [cid:1baf66d8-a732-4aa9-ae50-4405f360f220][cid:d6064b7c-738c-46af-a442-723c71a6df11] CONFIDENTIALITY: The contents of this e-mail are confidential and intended only for the above addressee(s). If you are not the intended recipient, or the person responsible for delivering it to the intended recipient, copying or delivering it to anyone else or using it in any unauthorized manner is prohibited and may be unlawful. If you receive this e-mail by mistake, please notify the sender and the systems administrator at straymail(a)rt-rk.com immediately.

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DTS, DTS-HD MA 5.1, DTS-HD MA 7.1, DTS X to stereo downmix normalization issue
by Petro Deineka 25 May '26

25 May '26

MPC-BE x64 Settings: Audio: Sound Processing: Channel Mixing - Stereo - Stereo Upmix in Decoder When downmixing from 7.1 or 5.1 to 2.0 stereo, matrix normalisation does not work with the DTS MA format. Downmixing currently works for TrueHD and AC3; E-AC3 always works. Please add downmixing support for DTS, DTS MA and DTS X. Subject: Incorrect downmix normalization and clipping when downmixing DTS-HD MA 7.1, or 5.1 to stereo Hello FFmpeg developers, I have encountered an issue with downmix normalization when converting or playing DTS-HD MA 7.1 audio tracks to stereo. Compared to Dolby formats (AC3, E-AC3, TrueHD), the DTS-HD MA downmix output is noticeably louder, which often leads to severe audio clipping. Additionally, ffplay reports an "Invalid downmix layout" warning during playback. Steps to reproduce / commands tested: 1. ffplay -downmix 2 input.mkv 2. ffmpeg -i input.mkv -ac 2 output.wav Stream details: - Audio: dts (dca) (DTS-HD MA), 48000 Hz, 7.1, s32p (24 bit) Observed behavior: - AC3, E-AC3, and TrueHD 7.1 streams downmix correctly with proper normalization. - DTS-HD MA 7.1 output is too loud and clips. - ffplay console output shows: "[dca @ ...] Invalid downmix layout" Environment: - FFmpeg version: 8.1.1 essentials build (Windows) - The issue is also reproducible in MPC-BE player (which relies on FFmpeg decoders internally). I suspect that the dca decoder either misinterprets the 7.1 channel layout during downmixing or does not apply the correct attenuation coefficients compared to the Dolby decoder implementations. Thank you for your time and for maintaining this great project!

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not selecting the correct default streams
by William C Bonner 24 May '26

24 May '26

I have a program that runs FFMPEG to stream video files to my TiVo. Sometimes a video file will not transfer because no streams get selected to copy. The metadata looks like it should work to me. I use the same command for each file other than the input file name. Can someone explain how I can get it to include the Audio and Video stream without hard coding the stream numbers, which obviously can change between files? Here's example output from a successful conversion and a failing conversion: C:\Users\Wim>C:\WINDOWS\ffmpeg.exe -hide_banner -i Success.mkv -map 0:d? -vcodec copy -bsf:v h264_mp4toannexb -b:v 30000k -maxrate 30000k -bufsize 8192k -acodec ac3 -b:a 448k -ar 48000 -f mpegts -y test.mpegts Input #0, matroska,webm, from 'Success.mkv': Metadata: encoder : libebml v1.4.5 + libmatroska v1.7.1 creation_time : 2026-05-23T18:02:18.000000Z Duration: 00:25:18.01, start: 0.000000, bitrate: 8446 kb/s Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 50 fps, 50 tbr, 1k tbn, start 0.004000 (default) Metadata: BPS : 8250568 DURATION : 00:25:18.001000000 NUMBER_OF_FRAMES: 75900 NUMBER_OF_BYTES : 1565546401 _STATISTICS_WRITING_APP: mkvmerge v98.0 ('Chonks') 64-bit _STATISTICS_WRITING_DATE_UTC: 2026-05-23 18:02:18 _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES Stream #0:1(eng): Audio: eac3, 48000 Hz, stereo, fltp, 192 kb/s (default) Metadata: BPS : 191991 DURATION : 00:25:17.920000000 NUMBER_OF_FRAMES: 47433 NUMBER_OF_BYTES : 36428544 _STATISTICS_WRITING_APP: mkvmerge v98.0 ('Chonks') 64-bit _STATISTICS_WRITING_DATE_UTC: 2026-05-23 18:02:18 _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES Stream mapping: Stream #0:0 -> #0:0 (copy) Stream #0:1 -> #0:1 (eac3 (native) -> ac3 (native)) Press [q] to stop, [?] for help Output #0, mpegts, to 'test.mpegts': Metadata: encoder : Lavf62.13.101 Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 30000 kb/s, 50 fps, 50 tbr, 90k tbn (default) Metadata: BPS : 8250568 DURATION : 00:25:18.001000000 NUMBER_OF_FRAMES: 75900 NUMBER_OF_BYTES : 1565546401 _STATISTICS_WRITING_APP: mkvmerge v98.0 ('Chonks') 64-bit _STATISTICS_WRITING_DATE_UTC: 2026-05-23 18:02:18 _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES Stream #0:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 448 kb/s (default) Metadata: encoder : Lavc62.29.100 ac3 BPS : 191991 DURATION : 00:25:17.920000000 NUMBER_OF_FRAMES: 47433 NUMBER_OF_BYTES : 36428544 _STATISTICS_WRITING_APP: mkvmerge v98.0 ('Chonks') 64-bit _STATISTICS_WRITING_DATE_UTC: 2026-05-23 18:02:18 _STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES [af#0:1 @ 00000247be2ea9c0] Reconfiguring filter graph because audio parameters changed to 48000 Hz, 5.1(side), fltp, downmix medatata changed [vost#0:0/copy @ 00000247bced0a80] Invalid DTS: 50760 PTS: 47160, replacing by guess [vost#0:0/copy @ 00000247bced0a80] Non-monotonic DTS; previous: 48961, current: 47160; changing to 48962. This may result in incorrect timestamps in the output file. [out#0/mpegts @ 00000247bcf5ea00] video:1528705KiB audio:83008KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 3.264436% frame=75900 fps=1659 q=-1.0 Lsize= 1664326KiB time=00:25:17.98 bitrate=8981.7kbits/s speed=33.2x elapsed=0:00:45.74 C:\Users\Wim>C:\WINDOWS\ffmpeg.exe -hide_banner -i Failure.mp4 -map 0:d? -vcodec copy -bsf:v h264_mp4toannexb -b:v 30000k -maxrate 30000k -bufsize 8192k -acodec ac3 -b:a 448k -ar 48000 -f mpegts -y test.mpegts Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Failure.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf62.12.100 Duration: 01:21:10.27, start: 0.000000, bitrate: 8256 kb/s Stream #0:0[0x1](eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 7995 kb/s, 50 fps, 50 tbr, 50k tbn, start 0.286000 (default) Metadata: handler_name : ?Apple Video Media Handler encoder : H264/AVC timecode : 00:00:00:00 Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 249 kb/s (default) Metadata: handler_name : ?Apple Sound Media Handler Stream #0:2[0x3](eng): Data: none (tmcd / 0x64636D74) Metadata: handler_name : ?Apple Video Media Handler timecode : 00:00:00:00 [out#0/mpegts @ 000001e4e8b315c0] Codec AVOption b:v (set bitrate (in bits/s)) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some decoder which was not actually used for any stream. [out#0/mpegts @ 000001e4e8b315c0] Codec AVOption b:a (set bitrate (in bits/s)) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some decoder which was not actually used for any stream. Stream mapping: Stream #0:2 -> #0:0 (copy) Output #0, mpegts, to 'test.mpegts': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf62.13.101 Stream #0:0(eng): Data: none (tmcd / 0x64636D74) Metadata: handler_name : ?Apple Video Media Handler timecode : 00:00:00:00 Press [q] to stop, [?] for help [mpegts @ 000001e4e8b316c0] Stream 0, codec none, is muxed as a private data stream and may not be recognized upon reading. [out#0/mpegts @ 000001e4e8b315c0] video:0KiB audio:0KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 18700.000000% size= 1KiB time=01:21:10.00 bitrate= 0.0kbits/s speed=3.01e+05x elapsed=0:00:00.01 C:\Users\Wim>ffmpeg -? ffmpeg version 2026-03-15-git-6ba0b59d8b-full_build-www.gyan.dev Copyright (c) 2000-2026 the FFmpeg developers built with gcc 15.2.0 (Rev11, Built by MSYS2 project) configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-cairo --enable-fontconfig --enable-iconv --enable-gnutls --enable-lcms2 --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libopenjpeg --enable-libquirc --enable-libuavs3d --enable-libxevd --enable-libzvbi --enable-liboapv --enable-libqrencode --enable-librav1e --enable-libsvtav1 --enable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxeve --enable-libxvid --enable-libaom --enable-libjxl --enable-libsvtjpegxs --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-openal --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-liblc3 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint --enable-whisper libavutil 60. 29.100 / 60. 29.100 libavcodec 62. 29.100 / 62. 29.100 libavformat 62. 13.101 / 62. 13.101 libavdevice 62. 4.100 / 62. 4.100 libavfilter 11. 15.101 / 11. 15.101 libswscale 9. 7.100 / 9. 7.100 libswresample 6. 4.100 / 6. 4.100 Universal media converter usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

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Corrupted mpegts packets...suddenly I see this more often
by Kevin Hise 20 May '26

20 May '26

It's likely a network setting. Not a network switch setting as I've seen it occur on the same computer and trying the different NICs it has using the same network switch. The effect is the same...some partial image at the top and the rest "smeared" vertically, like falling water. It'll not happen. It'll not happen in older FFmpeg / SDL2 applications I've written and does happen in later ones (so more recent lib versions). It'll happen on one NIC and not on the other for the same workstation....all running at 1Gig. Windows is all I've tested this on. There's no av_dict_set() options that I've found that make a difference. Errors about corrupted packets spew into the logs. The image attached is a multicast stream from a Costar camera....and should be monochrome. I've cropped the image for size. Apologies about the larger one I sent earlier. It's got me stumped and I'm wishing I could give the admin(s) some info...otherwise they just shrug and blame the programmer. It worked last week. Doesn't work this week. Absolutely no changes to any code. But I've seen it several times lately. Thank you. --kh;

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Audio manipulation question.
by Hwaen Ch'uqi 18 May '26

18 May '26

Greetings. I have a video file in which the audio comes only out of one ear - the left ear - when listening with headphones. Is there a way to pipe the left-ear sound to the right as well? Currently, there is no sound whatsoever in the right ear. Thank you for any help! Hwaen Ch'uqi

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ffmpeg installed OK but cannot find input files
by Richard 16 May '26

16 May '26

verified correct installation by checking version, and put sequentially numbered img files in a folder called "input" but no matter where I put that folder, ffmpeg cannot find them... screenshot follows - please advise? -- Richard Nourse Website:www.grumpyoldgits.org -- This email has been checked for viruses by Avast antivirus software. www.avast.com

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ISSUE ABOUT AUDIO-VISUAL DELAY
by Hervé ANSELME 13 May '26

13 May '26

Hello all, I am using ffmpeg, release 6.1, running on Windows 11 Family. I'm experiencing an issue after re-encoding a video with ffmpeg : at the beginning of the play of the re-encoded video, the audio and video are in sync ; after a while, however, there is a delay between the video and the audio ; and from that point, the delay is not constant ; it increases as the video-reading progresses. Has anyone have ever met such issue ? And have an idea how to fix it ? It's strange because I've used FFmpeg a lot up until now, and I've never met this kind of issue before ... Thank you in advance for your replies and advices. Regards, HA

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Closed Caption insertion
by Ryan Cola 01 May '26

01 May '26

Hello, I am looking to use ffmpeg to inject EIA-608/708 using a Scenarist Closed Caption file during the transcode process and creating an mpeg-ts output. Does ffmpeg currently support that, and if not, is it something that can be developed? Thanks, rccola875

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