Keep MOV tags in "meta" atom during transcode

[Jérôme Martinez]

Some tags in "moov"/"udta" atom (e.g. "©nam", but not "©src") are kept during a transcode from MOV to MOV, but all tags in "moov"/"meta" atom are discarded, despite the fact they are listed in the Output section during transcode:

How to reproduce:

% ffmpeg -i input.mov output.mov
ffmpeg version N-88514-gd5995c531d Copyright (c) 2000-2017 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-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-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  libavutil      56.  0.100 / 56.  0.100
  libavcodec     58.  1.100 / 58.  1.100
  libavformat    58.  0.102 / 58.  0.102
  libavdevice    58.  0.100 / 58.  0.100
  libavfilter     7.  0.101 /  7.  0.101
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    title           : test nam
    encoder         : Lavf58.0.102
    net.mediaarea.blablablabla01: test    1
    net.mediaarea.blablabla02: test       2
  Duration: 00:00:00.04, start: 0.000000, bitrate: 465 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 264 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : DataHandler
      encoder         : Lavc58.1.100 libx264
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 000001f556dceb20] using SAR=1/1
[libx264 @ 000001f556dceb20] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
[libx264 @ 000001f556dceb20] profile High, level 1.3
[libx264 @ 000001f556dceb20] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=7 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mov, to 'output.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    title           : test nam
    net.mediaarea.blablabla02: test       2
    net.mediaarea.blablablabla01: test    1
    encoder         : Lavf58.0.102
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      handler_name    : DataHandler
      encoder         : Lavc58.1.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=    1 fps=0.0 q=28.0 Lsize=       2kB time=00:00:00.00 bitrate=219179.5kbits/s speed=0.00311x
video:1kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 60.074905%
[libx264 @ 000001f556dceb20] frame I:1     Avg QP:15.87  size:   646
[libx264 @ 000001f556dceb20] mb I  I16..4: 90.7%  4.7%  4.7%
[libx264 @ 000001f556dceb20] 8x8 transform intra:4.7%
[libx264 @ 000001f556dceb20] coded y,uvDC,uvAC intra: 2.8% 12.7% 7.0%
[libx264 @ 000001f556dceb20] i16 v,h,dc,p: 83% 11%  6%  0%
[libx264 @ 000001f556dceb20] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 36% 29% 29%  7%  0%  0%  0%  0%  0%
[libx264 @ 000001f556dceb20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 40% 53%  5%  0%  1%  0%  0%  0%  1%
[libx264 @ 000001f556dceb20] i8c dc,h,v,p: 49% 11% 39%  0%
[libx264 @ 000001f556dceb20] kb/s:129.20

same with " -map_metadata 0".

metadata from "meta" atom should be kept (mapped to the output file), preferably by default ("ffmpeg -i input.mov output.mov") or with " -map_metadata 0".

File with "udta" and "meta" atoms attached.

[Jérôme Martinez]

With both udta and meta metadata atoms