hello guys
i have a input.mkv which has constant frame rate
[Attachment 63796 - Click to enlarge]
when am changing wrapper MKV to MP4
with this code
ffmpeg -i input.mkv -c copy output.mp4
it copies all streams but it makes my output video stream's frame rate variable
[Attachment 63797 - Click to enlarge]
why this happening?
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Anonymous543Guest
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+1
I have a similar but no doubt unrelated issue with output from v4l2 encoder=h264_v4l2m2m -
The default time base for MP4 is 90000. That is not evenly divisible by a frame rate of 24000/1001. You get 90000 / 24000 * 1000 = 3753.75, ie, each frame needs to be displayed for 3753.75/90000 seconds. But frame durations can only be expressed as integers so the muxer alternates between 3753/90000 (one time) and 3754/90000 (3 times) to make an average of 3753.75.
Actually, given the minimum frame rate of 23.564 and maximum frame rate of 24.390 some time base other than 90000 is being used (I think 16000). But the issue is the same. The muxer is alternating between two different values to achieve the exact average frame rate.
And MKV does the same thing, it just doesn't label the file as variable frame rate. Drag/drop Batch file:
You can use ffprobe to see the timestamps. pkt_dts is the time at which each frame is displayed (pkt_dts / timebase).
That gives the display time of each frame (time base not shown). The resulting CSV file can be opened in Notepad or imported into a spreadsheet.Code:ffprobe -v 32 -stats -y -hide_banner -i %1 -select_streams v -print_format csv -of csv -show_entries "frame=pkt_dts" >> "%~nx1.csv"
Last edited by jagabo; 14th Mar 2022 at 08:22.
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Anonymous543Guest
so how can i convert a mkv video which has constant frame rate to mp4 without messing frame rate or time code?
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remux it simply and that's it
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Mediainfo is wrong about "contant frame rate".
MKV is technically always VFR for "23.976" (24000/1001) . The problem is the MKV container. The MKV container specs stipulate a timebase of 1/1000s only, so there is "jitter" and rounding errors in the timestamps. FFmpeg is copying those rounding errors to the MP4 container. (You can set the ffmpeg output MP4 container timebase to 24000 using -video_track_timescale 24000 , but it won't fix it because it copies the input MKV's already rounded timestamps)
If you extract a 24000/1001 MKV timestamps with mkvextract, you get this. There is rounding up and down in the delta between frames. It's not really "constant" framerate, because there are 1ms rounding deviations
Code:# timestamp format v2 0 42 83 125 167 209 250
In contrast, a 24000/1001 MP4 has a timebase of 1/24000s , so there are no ms rounding errors. It looks like this
Code:# timecode format v2 0 41.7083333333333 83.4166666666667 125.125 166.833333333333 208.541666666667 250.25
One way to "fix" the ffmpeg issue is to use mp4fpsmod. It also supports in-place editing (modify file directly), but you could argue that it's safer to use streamcopy
Code:"mp4fpsmod" "input.mp4" --fps 0:24000/1001 -o "output.mp4"
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Hello. Similarly, with this one the input is 25fps interlaced CFR and always produces VFR and I am not sure why.
The filter_complex stuff is just tinkering to see what happens but the result is the same VFR.
(It always produces "CBR" but that's another issue).
(The extra commandline options are due to a recently submitted patch but have zero effect on the outcome).
Suggestions welcomed.
Code:/usr/local/bin/ffmpeg -hide_banner -stats -v debug \ -sws_flags lanczos+accurate_rnd+full_chroma_int+full_chroma_inp \ -fflags +igndts \ -i "./some_test_input_file_tiny_2.mp4" \ -vsync cfr \ -strict experimental \ -filter_complex "[0:v]yadif=0:0:0,format=pix_fmts=yuv420p[vid0];[vid0]setpts=PTS-STARTPTS[vid1];[vid1]setpts=N/(25*TB)[vidX];[0:a]asetpts=PTS-STARTPTS[aud0];[aud0]asetpts=N/(SR*TB)[aud1];[aud1]aresample=async=1000[audX]" -map [vidX] -map [audX] \ -c:v h264_v4l2m2m \ -pix_fmt yuv420p \ -rc VBR \ -b:v 4000000 \ -qmin 10 -qmax 51 \ -profile:v high \ -level 4.2 \ -shm separate_buffer \ -rsh 0 \ -g:v 25 \ -movflags +faststart+write_colr \ -c:a libfdk_aac -cutoff 20000 -ab 256k -ar 48000 \ -y "./some_test_input_file_tiny_transcoded_h264_VBR_g25_b_YEScorrections_v4l2m2m.mp4"
Code:General Count : 331 Count of stream of this kind : 1 Kind of stream : General Kind of stream : General Stream identifier : 0 Count of video streams : 1 Count of audio streams : 1 Video_Format_List : AVC Video_Format_WithHint_List : AVC Codecs Video : AVC Audio_Format_List : AAC LC Audio_Format_WithHint_List : AAC LC Audio codecs : AAC LC Complete name : ./some_test_input_file_tiny_transcoded_h264_VBR_g25_b_YEScorrections_v4l2m2m.mp4 Folder name : . File name extension : some_test_input_file_tiny_transcoded_h264_VBR_g25_b_YEScorrections_v4l2m2m.mp4 File name : some_test_input_file_tiny_transcoded_h264_VBR_g25_b_YEScorrections_v4l2m2m File extension : mp4 Format : MPEG-4 Format : MPEG-4 Format/Extensions usually used : braw mov mp4 m4v m4a m4b m4p m4r 3ga 3gpa 3gpp 3gp 3gpp2 3g2 k3g jpm jpx mqv ismv isma ismt f4a f4b f4v Commercial name : MPEG-4 Format profile : Base Media Internet media type : video/mp4 Codec ID : isom Codec ID : isom (isom/iso2/avc1/mp41) Codec ID/Url : http://www.apple.com/quicktime/download/standalone.html CodecID_Compatible : isom/iso2/avc1/mp41 File size : 995559 File size : 972 KiB File size : 972 KiB File size : 972 KiB File size : 972 KiB File size : 972.2 KiB Duration : 2040 Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 00:00:02.040 Duration : 00:00:02:02 Duration : 00:00:02.040 (00:00:02:02) Overall bit rate mode : CBR Overall bit rate mode : Constant Overall bit rate : 3904153 Overall bit rate : 3 904 kb/s Frame rate : 25.490 Frame rate : 25.490 FPS Frame count : 52 Stream size : 4001 Stream size : 3.91 KiB (0%) Stream size : 4 KiB Stream size : 3.9 KiB Stream size : 3.91 KiB Stream size : 3.907 KiB Stream size : 3.91 KiB (0%) Proportion of this stream : 0.00402 HeaderSize : 2651 DataSize : 992908 FooterSize : 0 IsStreamable : Yes File last modification date : UTC 2022-03-14 19:30:58 File last modification date (local) : 2022-03-15 06:00:58 Writing application : Lavf59.18.101 Writing application : Lavf59.18.101 Video Count : 378 Count of stream of this kind : 1 Kind of stream : Video Kind of stream : Video Stream identifier : 0 StreamOrder : 0 ID : 1 ID : 1 Format : AVC Format : AVC Format/Info : Advanced Video Codec Format/Url : http://developers.videolan.org/x264.html Commercial name : AVC Format profile : High@L4.2 Format settings : CABAC / 1 Ref Frames Format settings, CABAC : Yes Format settings, CABAC : Yes Format settings, Reference frames : 1 Format settings, Reference frames : 1 frame Internet media type : video/H264 Codec ID : avc1 Codec ID/Info : Advanced Video Coding Duration : 2040 Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 00:00:02.040 Duration : 00:00:02:02 Duration : 00:00:02.040 (00:00:02:02) Duration_FirstFrame : -40 Duration_FirstFrame : -40 ms Duration_FirstFrame : -40 ms Duration_FirstFrame : -40 ms Duration_FirstFrame : -00:00:00.040 Bit rate mode : CBR Bit rate mode : Constant Bit rate : 3631337 Bit rate : 3 631 kb/s Nominal bit rate : 4000000 Nominal bit rate : 4 000 kb/s Maximum bit rate : 4000000 Maximum bit rate : 4 000 kb/s Width : 1920 Width : 1 920 pixels Height : 1080 Height : 1 080 pixels Stored_Height : 1088 Sampled_Width : 1920 Sampled_Height : 1080 Pixel aspect ratio : 1.000 Display aspect ratio : 1.778 Display aspect ratio : 16:9 Rotation : 0.000 Frame rate mode : VFR Frame rate mode : Variable Frame rate : 25.490 Frame rate : 25.490 FPS Minimum frame rate : 25.000 Minimum frame rate : 25.000 FPS Maximum frame rate : 25.049 Maximum frame rate : 25.049 FPS Original frame rate : 30.000 Original frame rate : 30.000 FPS Frame count : 52 Color space : YUV Chroma subsampling : 4:2:0 Chroma subsampling : 4:2:0 Bit depth : 8 Bit depth : 8 bits Scan type : Progressive Scan type : Progressive Bits/(Pixel*Frame) : 0.069 Stream size : 925998 Stream size : 904 KiB (93%) Stream size : 904 KiB Stream size : 904 KiB Stream size : 904 KiB Stream size : 904.3 KiB Stream size : 904 KiB (93%) Proportion of this stream : 0.93013 Buffer size : 62499840 colour_description_present : Yes colour_description_present_Source : Container Color range : Limited colour_range_Source : Container colour_primaries_Source : Container transfer_characteristics_Source : Container matrix_coefficients_Source : Container Codec configuration box : avcC Audio Count : 282 Count of stream of this kind : 1 Kind of stream : Audio Kind of stream : Audio Stream identifier : 0 StreamOrder : 1 ID : 2 ID : 2 Format : AAC Format : AAC LC Format/Info : Advanced Audio Codec Low Complexity Commercial name : AAC Format_AdditionalFeatures : LC Codec ID : mp4a-40-2 Duration : 2040 Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 2 s 40 ms Duration : 00:00:02.040 Duration : 00:00:02:02 Duration : 00:00:02.040 (00:00:02:02) Source duration : 2083 Source duration : 2 s 83 ms Source duration : 2 s 83 ms Source duration : 2 s 83 ms Source duration : 00:00:02.083 Source_Duration_LastFrame : -8 Source_Duration_LastFrame : -8 ms Source_Duration_LastFrame : -8 ms Source_Duration_LastFrame : -8 ms Source_Duration_LastFrame : -00:00:00.008 Bit rate mode : CBR Bit rate mode : Constant Bit rate : 256985 Bit rate : 257 kb/s Channel(s) : 2 Channel(s) : 2 channels Channel positions : Front: L R Channel positions : 2/0/0 Channel layout : L R Samples per frame : 1024 Sampling rate : 48000 Sampling rate : 48.0 kHz Samples count : 97920 Frame rate : 46.875 Frame rate : 46.875 FPS (1024 SPF) Frame count : 96 Source frame count : 98 Compression mode : Lossy Compression mode : Lossy Stream size : 65560 Stream size : 64.0 KiB (7%) Stream size : 64 KiB Stream size : 64 KiB Stream size : 64.0 KiB Stream size : 64.02 KiB Stream size : 64.0 KiB (7%) Proportion of this stream : 0.06585 Source stream size : 66902 Source stream size : 65.3 KiB (7%) Source stream size : 65 KiB Source stream size : 65 KiB Source stream size : 65.3 KiB Source stream size : 65.33 KiB Source stream size : 65.3 KiB (7%) Source_StreamSize_Proportion : 0.06720 Default : Yes Default : Yes Alternate group : 1 Alternate group : 1 Source_Delay : -43 Source_Delay_Source : Container
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It's a kludge, but the easiest way I know of to convert NTSC frame rate MKV files to CFR MP4 files is to remux from MKV to AVI, then from AVI to MP4.
MediaInfo will show it as CFR and it the timestamps will increase by 1001 (ie, 1001/24000, 2002/24000, 3003/24000, etc).Code:ffmpeg -i 24p.mkv -c copy -r 24000/1001 -bsf:v h264_mp4toannexb 24p.avi ffmpeg -loglevel error -i 24p.avi -c copy 24p.mp4 del 24p.avi
Slightly less kludgy, demux to a h264 elementary stream, then remux to mp4:
Code:ffmpeg -i 24p.mkv -c copy -f h264 24p.h264 ffmpeg -loglevel error -r 24000/1001 -i 24p.h264 -c copy 24p.mp4 del 24p.h264
Last edited by jagabo; 14th Mar 2022 at 18:18. Reason: added h264 elementary stream method
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Anonymous543Guest
Too much rocket science behind this
i only understood that when we convert MKV which has 24000/1001 constant framerate to MP4 it messes some frame time codes and makes constant frame rate to variable
you mean like this?remux it simply and that's it
ffmpeg -i input.mkv output.mp4
this works well output frame rate remains constant 24000/1001 in mp4 wrapper
[Attachment 63809 - Click to enlarge]
but.. in this process video gets rencoded and thats why it may lose some quality and also output file size higher then input
so this is not a good solution
when we remux containers it rencodes video
so i did one more experiment with input.mkv(which has constant frame rate)
and did 2 pass encoding with output of mp4 container
this encoding was also failed with incomplete cu tree file errorCode:ffmpeg -y -i input.mkv -c:v libx265 -preset ultrafast -b:v 336k -x265-params pass=1 -an -sn -f null NUL && ^ ffmpeg -i input.mkv -c:v libx265 -preset ultrafast -b:v 336k -x265-params pass=2 -an -sn output.mp4
question is still there
i have mkv video file which has constant frame rate and i wanna copy video streams in mp4 container without messing frame rate with ffmpegLast edited by Anonymous543; 15th Mar 2022 at 02:02. Reason: added remuxed output mediainfo
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NoOriginally Posted by kirito
If you want constant framerate in mp4 (no advantage at all) follow jagabo's instructions:
1) remux your mkv to avi
2) remux the avi to mp4
Just tested it with clever FFmpeg-GUI -
Anonymous543Guest
https://files.videohelp.com/u/301063/movie.mkv
i want this video in mp4 wrapper without rencode with constant frame rate
tried this code
ffmpeg -i movie.mkv -c copy output.mp4
but it makes frame rate mode variable
and
ffmpeg -i movie.mkv -c copy output.avi
this makes video unplayable -
Here's a drag/drop batch file that uses the AVI intermediate method in post #8.
It needed a slight modification to work with HEVC. And it works specifically for 24000/1001 fps. I'm sure you can figure out how to modify it for other frame rates.Code:ffmpeg -i "%~dpnx1" -c copy -r 24000/1001 -bsf:v hevc_mp4toannexb -vtag hevc "%~dpn1.avi%" ffmpeg -loglevel error -i "%~dpn1.avi" -c copy "%~dpn1".mp4 del "%~dpn1.avi"
Last edited by jagabo; 15th Mar 2022 at 07:22.
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1) ffmpeg -r 24000/1001 -i movie.mkv -c copy -vtag hvc1 movie.aviOriginally Posted by kirito
2) ffmpeg -i movie.avi -c copy movie.mp4 -
Anonymous543Guesti never used batch/.bat files for encoding thats why....its liltle confusingOriginally Posted by jagabo
-r 24000/1001 -bsf:v hevc_mp4toannexb -vtag hevc
-loglevel error
explain this commands..whats its doing? -
Instead of always asking new questions, you should first say thank you and learn for yourself.
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Anonymous543GuestI don't know what exactly those command will do with my video stream I'll thank you guys later when I'll knowInstead of always asking new questions, you should first say thank you and learn for yourself.
-r is for framerate i guess
i have no idea of
-bsf:v hevc_mp4toannexb
-vtag hevc
-loglevel error -
-r 24000/1001 = set constant frame rate to 24000/1001 for AVI file, https://ffmpeg.org/ffmpeg.html#Video-Options
-bsf:v hevc_mp4toannexb = adjustment of hevc stream organization, https://ffmpeg.org/ffmpeg-bitstream-filters.html#hevc_005fmp4toannexb
-vtag hevc = set AVI fourcc (codec identifier) to hevc, https://ffmpeg.org/ffmpeg.html#Advanced-Video-options and https://docs.microsoft.com/en-us/windows/win32/directshow/avi-riff-file-reference
-loglevel error = only show error message otherwise lots of warning messages about unset timestamps will slow the processing, https://ffmpeg.org/ffmpeg.html#Generic-options -
Anonymous543Guest
@jagabo @ProWo
i did liltle research and made one more method to keep frame rate constant in mp4 which is similar to yours methods
https://superuser.com/questions/678897/extract-hevc-bitstream-with-ffmpeg
here goes my explaination
step 1 : extract raw hevc stream from MKV file which is called Annex B format
by this command
note : - output file name out.h265Code:ffmpeg -i input.mkv -c copy -bsf hevc_mp4toannexb out.h265
step 2 : remux output of step 1 to mp4 with this commands
Code:ffmpeg -i out.h265 -c copy output.mp4
thats all works well
by the way why did you suggested to remux to avi first and then mp4?
and also in my method specifying -r also not needed ,all gets copied automatically i guess
i think our all methods are same?Last edited by Anonymous543; 16th Mar 2022 at 06:46.
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Audio can be remuxed along with the video. With an elementary stream you need some extra commands in the final mux to include the audio:Originally Posted by kirito
Also, I noticed that when using an AVI intermediate the output mp4 comes out VFR if the source video is HEVC. I was testing with an AVC source where it came out CFR. I'm not sure why there is a difference.Code:ffmpeg -i input.mkv -c copy -bsf hevc_mp4toannexb out.h265 ffmpeg -i out.h265 -i input.mkv -c copy -map 0:v -map 1:a output.mp4 del out.h265
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Anonymous543GuestOhh yea this ffmpeg codecs surprises me always with output resultsAlso, I noticed that when using an AVI intermediate the output mp4 comes out VFR if the source video is HEVC. I was testing with an AVC source where it came out CFR. I'm not sure why there is a difference.
May be that's why i like CLI of ffmpeg ,i can choose easy way of GUI but in that no new options,
But in CLI i discover something new and different everyday -
Alternatively, you could also use MP4FPSMod. I had this exact same problem a while back, and this is what fixed it.
Use this command:
Doesn't re-encode, just fixes the timestamps.Code:"mp4fpsmod.exe" --fps 0:24000/1001 "file.mp4" -o "file_fixed.mp4"
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No, see my post above #15Originally Posted by jagabo
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I realize this is an older thread, but i recently had this variable frame rate issue and found an easy solution.
If you have VideoReDo, open the mkv in the Quick Stream Fixer and set the output profile for mp4. The mp4 created will be constant frame rate. The file will just be remuxed, not re-encoded.
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