[Cin] MTS files; concat demuxer / protocol

[Terje J. Hanssen]

Den 17.09.2024 14:11, skrev Stefan de Konink via Cin:
> There are quite some topics online mentioning the when MTS files 
> (exceeding 2GB) are naively added to a timeline. The problem that then 
> appears is that the audio is typically "shorter" than the video, and 
> it does not appear in the interface. Cinelerra will even shift the 
> audio track under the previous track.
>
> It is mentioned that Adobe Premiere is able to parse an AVCHD 
> structure, including the ability to use meta information such as 
> timecode, which is not available from MTS files directly.
>
> Other workarounds that are mentioned to first join the MTS files. 
> FFmpeg has the option concat demuxer and concat protocol. But it pulls 
> another surprise...


Have you tried simple "cat" to join clips in a Linux terminal?

I have not tested this with MTS files, but it works for my HDV.m2t files 
(mpeg2 video/mp2 audio)

     cat file1 file2 > file1+2

file1+2 may load directly in Cingg if the clips were continuously 
auto-clipped.

For random clips, there might arise a black segment between the clips.

In my experience this is possible to cleanup first with

     fmpeg -hide_banner -i file1+2 -reset_timestamps 1 -c copy 
file1+2_cleanup


ffmpeg or ffprobe may still complain about single "Packet corrupt" or 
"timestamp discontinuity", which I simply have ignored.


>
>
> ffmpeg -i "concat:00152.MTS|00153.MTS|00154.MTS" -vcodec copy -acodec 
> copy test.ts
> ffmpeg version n7.0.1 Copyright (c) 2000-2024 the FFmpeg developers
>   built with gcc 14.1.1 (GCC) 20240522
>   configuration: --prefix=/usr --disable-debug --disable-static 
> --disable-stripping --enable-amf --enable-avisynth --enable-cuda-llvm 
> --enable-lto --enable-fontconfig --enable-frei0r --enable-gmp 
> --enable-gpl --enable-ladspa --enable-libaom --enable-libass 
> --enable-libbluray --enable-libbs2b --enable-libdav1d --enable-libdrm 
> --enable-libdvdnav --enable-libdvdread --enable-libfreetype 
> --enable-libfribidi --enable-libgsm --enable-libharfbuzz 
> --enable-libiec61883 --enable-libjack --enable-libjxl 
> --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb 
> --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopenmpt 
> --enable-libopus --enable-libplacebo --enable-libpulse 
> --enable-librav1e --enable-librsvg --enable-librubberband 
> --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt 
> --enable-libssh --enable-libsvtav1 --enable-libtheora --enable-libv4l2 
> --enable-libvidstab --enable-libvmaf --enable-libvorbis 
> --enable-libvpl --enable-libvpx --enable-libwebp --enable-libx264 
> --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid 
> --enable-libzimg --enable-mbedtls --enable-nvdec --enable-nvenc 
> --enable-opencl --enable-opengl --enable-shared --enable-vapoursynth 
> --enable-version3 --enable-vulkan
>   libavutil      59.  8.100 / 59.  8.100
>   libavcodec     61.  3.100 / 61.  3.100
>   libavformat    61.  1.100 / 61.  1.100
>   libavdevice    61.  1.100 / 61.  1.100
>   libavfilter    10.  1.100 / 10.  1.100
>   libswscale      8.  1.100 /  8.  1.100
>   libswresample   5.  1.100 /  5.  1.100
>   libpostproc    58.  1.100 / 58.  1.100
> Input #0, mpegts, from 'concat:00152.MTS|00153.MTS|00154.MTS':
>   Duration: 00:25:04.36, start: 1.040000, bitrate: 24022 kb/s
>   Program 1
>   Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), 
> yuv420p(top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn
>   Stream #0:1[0x1100]: Audio: pcm_bluray (HDMV / 0x564D4448), 48000 
> Hz, stereo, s16, 1536 kb/s
>   Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle (pgssub) 
> ([144][0][0][0] / 0x0090), 1920x1080
> File 'test.ts' already exists. Overwrite? [y/N] y
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)
>   Stream #0:1 -> #0:1 (copy)
> Output #0, mpegts, to 'test.ts':
>   Metadata:
>     encoder         : Lavf61.1.100
>   Stream #0:0: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(top 
> first), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 25 fps, 25 tbr, 90k tbn
>   Stream #0:1: Audio: pcm_bluray (HDMV / 0x564D4448), 48000 Hz, 
> stereo, s16, 1536 kb/s
> Press [q] to stop, [?] for help
> [mpegts @ 0x600ed54cf540] Stream 1, codec pcm_bluray, is muxed as a 
> private data stream and may not be recognized upon reading.
>
> This results in a video file cinelerra (and others) cannot read.
>
> Instead if we would say do it in pcm_sb16le we would be able to show 
> that the MTS file does contain the audio and FFmpeg is able to read 
> it. I have attached a screenshot showing what happens.
>
> I wonder: could we in Cinelerra implement something that would not 
> open a file as single file or EDL, but instead a concat set of files?
>
> Something in the drop down: "Create a single new resource only". That 
> single resource should be opened via the concat protocol, and then be 
> able as single instance. An EDL, but then at protocol level.
>
> I think this would make sense for many recordings that are split due 
> to filesystem limits, but even for image sequences, if they could be 
> directly opened and edited as if they were single files.
>
>
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