[FFmpeg-user] concatenating files in FFMPEG causing the wrong file length
andrei ka
andrei.k.gml at gmail.com
Wed Oct 7 15:16:19 EEST 2020
hi,
try this patch :
http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20180316/739542e4/attachment.obj
(explained here:
https://ffmpeg.org/pipermail/ffmpeg-devel/2018-March/226706.html)
but it works up to 4.1.3 .
&rei
On Wed, Oct 7, 2020 at 1:46 PM Philip Orrill <philip.orrill at outlook.com>
wrote:
> Hi there
>
> I have an input coming from an rtsp source in 2 second increments to
> convert
> to a HLS stream. The stream itself seems fine. However I do sometimes get
> the warning:
>
> *Non-monotonous DTS in output stream 0:0*
>
> my current command for obtaining the stream is
>
> *-stimeout 60000000 -y -rtsp_transport tcp -use_wallclock_as_timestamps 1
> -i
> {url} -c:v copy -hls_segment_type mpegts -hls_time 2 -hls_list_size 5 -f
> hls
> output.m3u8*
>
> The idea was to then concatenate these together to get a full file. However
> the concatenation generates a file with a very different length. I may do a
> 10 minute video. When concatenated this comes out to be 15 minutes or more.
>
> I figured this was due to the warnings. I thought I could process each
> segment and re-generate the timestamps. I know all my files are around 2
> second long for instance. So re-generate and then concatenate.
>
> I am so far having no luck.
>
> *I have tried a few different commands below are some examples:*
>
> *Reset timestamps* -i "D:\TestFiles\output18.ts" -c:v libx264 -crf 17
> -preset veryfast -reset_timestamps 1 "D:\TestFiles\output18_new.ts"
>
> *setting framerate and fflags* -i "D:\TestFiles\output18.ts" -r 20 -c:v
> libx264 -preset veryfast -g 20 -fflags +genpts "D:\TestFiles\output18.mp4"
>
> *Vsync and wall clock* -i "D:\TestFiles\output18.ts" -r 20
> -use_wallclock_as_timestamps 1 -c:v libx264 -preset veryfast -vsync drop
> "D:\TestFiles\output18.mp4"
>
> The files are generated and I can concatenate them but the time is still
> off
> by a lot.
>
> Interestingly even when converting a single file from just a ts to an mp4
> the files changes more then I expect.
>
> For example the file size goes from 260KB to 694KB
>
> I have done a lot of tests and they all seem to produce slightly different
> wrong results.
>
> Here is an example from FFPROBE on the 2 files I have run.
>
> *ts file*
> ffprobe version git-2019-11-11-20c5f4d Copyright (c) 2007-2019 the FFmpeg
> developers
> built with gcc 9.2.1 (GCC) 20191010
> configuration: --enable-gpl --enable-version3 --enable-sdl2
> --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass
> --enable-libdav1d --enable-libbluray --enable-libfreetype
> --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
> --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy
> --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx
> --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265
> --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp
> --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc
> --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom
> --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va
> --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
> --enable-libopenmpt --enable-amf
> libavutil 56. 35.101 / 56. 35.101
> libavcodec 58. 61.100 / 58. 61.100
> libavformat 58. 34.101 / 58. 34.101
> libavdevice 58. 9.100 / 58. 9.100
> libavfilter 7. 66.100 / 7. 66.100
> libswscale 5. 6.100 / 5. 6.100
> libswresample 3. 6.100 / 3. 6.100
> libpostproc 55. 6.100 / 55. 6.100
> Input #0, mpegts, from 'D:\TestFiles\output18.ts':
> Duration: 00:00:01.99, start: 38.121067, bitrate: 1034 kb/s
> Program 1
> Metadata:
> service_name : Media Presentation
> service_provider: FFmpeg
> Stream #0:0[0x100]: Video: h264 (Main) ([27][0][0][0] / 0x001B),
> yuv420p(tv, bt709, progressive), 1920x1080, 20 fps, 24.92 tbr, 90k tbn, 40
> tbc
>
> *MP4*
> ffprobe version git-2019-11-11-20c5f4d Copyright (c) 2007-2019 the FFmpeg
> developers
> built with gcc 9.2.1 (GCC) 20191010
> configuration: --enable-gpl --enable-version3 --enable-sdl2
> --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass
> --enable-libdav1d --enable-libbluray --enable-libfreetype
> --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
> --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy
> --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx
> --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265
> --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp
> --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc
> --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom
> --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va
> --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
> --enable-libopenmpt --enable-amf
> libavutil 56. 35.101 / 56. 35.101
> libavcodec 58. 61.100 / 58. 61.100
> libavformat 58. 34.101 / 58. 34.101
> libavdevice 58. 9.100 / 58. 9.100
> libavfilter 7. 66.100 / 7. 66.100
> libswscale 5. 6.100 / 5. 6.100
> libswresample 3. 6.100 / 3. 6.100
> libpostproc 55. 6.100 / 55. 6.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\TestFiles\output18.mp4':
> Metadata:
> major_brand : isom
> minor_version : 512
> compatible_brands: isomiso2avc1mp41
> encoder : Lavf58.34.101
> Duration: 00:00:02.05, start: 0.000000, bitrate: 1151 kb/s
> Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1920x1080, 1145 kb/s, 20 fps, 20 tbr, 10240 tbn, 40 tbc (default)
> Metadata:
> handler_name : VideoHandler
>
>
> The file length is slightly longer on the mp4 at 2.05 instead of 1.99. Some
> other items have also changed. The length seems to be consistently 2.05 but
> the bits and tbn seem to change slightly depending on what inputs I use for
> encoding to the mp4.
>
> All I am trying to achieve.
> I have 10 minutes of ts files. I concatenate them and have a 10 minute
> video. My guess is that due to the issues with timestamps or an
> inconsistent
> frame rate it is causing the issues with the concatenation.
>
> I don't mind re-encoding the files and generating new timestamps etc. I
> can't seem to quite get it to work. I'm not sure if i'm missing something.
> I
> have been banging my head against this for a few days now.
>
> I know the length of the file (ffprobe gets it correct). I know the fps it
> should be, so I can add add/remove frames if needed.
>
> It would be appreciated if someone could point me in the correct direction.
>
> thanks
>
>
>
>
> --
> Sent from: http://www.ffmpeg-archive.org/
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