ffmpeg for windows: error when concatenating videos - ffmpeg

Question

i have extracted a few clips from a video file of resolution 1920x816 called ca0.mp4...ca9.mp4 using the command
ffmpeg -i ./ca.mkv -ss 00:53:24 -t 00:01:30 ca0.mp4
Then i created a black video using
ffmpeg -f lavfi -i color=black:s=1920x816:r=24000/1001 -f lavfi -i anullsrc -ar 48000 -ac 2 -t 00:00:02 empty.mp4
now i want to concencate the clips with the black video between them. Therefore i created a file list.txt:
file 'ca0.mp4'
file 'empty.mp4'
file 'ca1.mp4'
file 'empty.mp4'
file 'ca2.mp4'
file 'empty.mp4'
file 'ca3.mp4'
file 'empty.mp4'
file 'ca4.mp4'
file 'empty.mp4'
file 'ca5.mp4'
file 'empty.mp4'
file 'ca6.mp4'
file 'empty.mp4'
file 'ca7.mp4'
file 'empty.mp4'
file 'ca8.mp4'
file 'empty.mp4'
file 'ca9.mp4'
and tried the command
ffmpeg -f concat -i list.txt -c:v qtrle -c:a copy ca.mp4
however, i get the following output:
ffmpeg version N-89940-gb1af0e23a3 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 7.2.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --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-libmfx --enable-amf --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth
libavutil 56. 7.100 / 56. 7.100
libavcodec 58. 9.100 / 58. 9.100
libavformat 58. 7.100 / 58. 7.100
libavdevice 58. 0.101 / 58. 0.101
libavfilter 7. 11.101 / 7. 11.101
libswscale 5. 0.101 / 5. 0.101
libswresample 3. 0.101 / 3. 0.101
libpostproc 55. 0.100 / 55. 0.100
[mov,mp4,m4a,3gp,3g2,mj2 # 000001e2cd155900] Auto-inserting h264_mp4toannexb bitstream filter
Guessed Channel Layout for Input Stream #0.1 : 5.1
Input #0, concat, from 'list.txt':
Duration: N/A, start: -0.021333, bitrate: 1894 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x816 [SAR 1:1 DAR 40:17], 1500 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc
Metadata:
handler_name : VideoHandler
Stream #0:1(ger): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 394 kb/s
Metadata:
handler_name : SoundHandler
Stream #0:2(eng): Data: bin_data (text / 0x74786574), 0 kb/s
Metadata:
handler_name : SubtitleHandler
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> qtrle (native))
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[mp4 # 000001e2cd213080] Could not find tag for codec qtrle in stream #0, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:0 --
Conversion failed!
can anyone tell me, what i did wrong?

Answer 1

As all files are already converted in .mp4 from .mkv
you may just need to copy the video codec too
ffmpeg -f concat -i list.txt -c:v copy -c:a copy ca.mp4
It will also speed up the process