[FFmpeg-user] How to access H.264 MP4 timecode data
Rio Kierkels
riokierkels at gmail.com
Fri Jan 31 16:57:27 CET 2014
On 31 January 2014 16:46, Francois Visagie <francois.visagie at gmail.com>wrote:
> > -----Original Message-----
> > From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> > bounces at ffmpeg.org] On Behalf Of Rio Kierkels
> > Sent: 31 January 2014 17:29
> > To: FFmpeg user questions
> > Subject: Re: [FFmpeg-user] How to access H.264 MP4 timecode data
> >
> > On 31 January 2014 16:22, Francois Visagie
> > <francois.visagie at gmail.com>wrote:
> >
> > > Hi All,
> > >
> > >
> > >
> > > I'm trying to access the timecode information stored by my camcorder,
> but
> > > not having any luck. The camera is set to H.264 MP4 recording in this
> case.
> > > According to ExifTool as well as ffprobe and ffmpeg the timecode data
> is
> > > present, but I haven't been able to find a way to extract it.
> > >
> > >
> > >
> > > According to the ffprobe manual:
> > >
> > > ffprobe supports Timecode extraction:
> > >
> > > * .
> > > * MOV timecode is extracted from tmcd track, so is available in
> the
> > > tmcd stream metadata ('-show_streams', see TAG:timecode).
> > >
> > > I would expect this to extract the timecode stream, but only 1
> > TAG:timecode
> > > value is printed. Also, the "unsupported codec" message does not
> inspire
> > > much confidence that this actually can work:
> > >
> > >
> > >
> > > C:\Users\fvisagie\Videos\Home Videos\Testing\AVCHD metadata
> > > subtitles>ffprobe -i MVI_0006.MP4 -select_streams 2 -show_streams
> > >
> > > ffprobe version N-54277-gff130d7 Copyright (c) 2007-2013 the FFmpeg
> > > developers
> > >
> > > built on Jun 30 2013 01:20:12 with gcc 4.7.3 (GCC)
> > >
> > > configuration: --enable-gpl --enable-version3 --disable-w32threads
> > > --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
> > > --enable-gnutls --enab
> > >
> > > le-iconv --enable-libass --enable-libbluray --enable-libcaca
> > > --enable-libfreetype --enable-libgsm --enable-libilbc
> --enable-libmodplug
> > > --enable-libmp3lame --ena
> > >
> > > ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
> > > --enable-libopus --enable-librtmp --enable-libschroedinger
> --enable-libsoxr
> > > --enable-libsp
> > >
> > > eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc
> > > --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-
> > libx264
> > > --enable-libxavs --
> > >
> > > enable-libxvid --enable-zlib
> > >
> > > libavutil 52. 37.101 / 52. 37.101
> > >
> > > libavcodec 55. 17.100 / 55. 17.100
> > >
> > > libavformat 55. 10.100 / 55. 10.100
> > >
> > > libavdevice 55. 2.100 / 55. 2.100
> > >
> > > libavfilter 3. 77.101 / 3. 77.101
> > >
> > > libswscale 2. 3.100 / 2. 3.100
> > >
> > > libswresample 0. 17.102 / 0. 17.102
> > >
> > > libpostproc 52. 3.100 / 52. 3.100
> > >
> > > Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'MVI_0006.MP4':
> > >
> > > Metadata:
> > >
> > > major_brand : mp42
> > >
> > > minor_version : 1
> > >
> > > compatible_brands: mp42avc1CAEP
> > >
> > > creation_time : 2014-01-30 17:57:13
> > >
> > > timecode : 11:54:27:03
> > >
> > > Duration: 00:00:03.84, start: 0.000000, bitrate: 35109 kb/s
> > >
> > > Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> > > 1920x1080, 34508 kb/s, 50 fps, 50 tbr, 50k tbn, 100k tbc
> > >
> > > Metadata:
> > >
> > > creation_time : 2014-01-30 17:57:13
> > >
> > > Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo,
> > > fltp, 253 kb/s
> > >
> > > Metadata:
> > >
> > > creation_time : 2014-01-30 17:57:13
> > >
> > > Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 1 kb/s
> > >
> > > Metadata:
> > >
> > > creation_time : 2014-01-30 17:57:13
> > >
> > > timecode : 11:54:27:03
> > >
> > > Unsupported codec with id 0 for input stream 2
> > >
> > > [STREAM]
> > >
> > > index=2
> > >
> > > codec_name=unknown
> > >
> > > codec_long_name=unknown
> > >
> > > profile=unknown
> > >
> > > codec_type=data
> > >
> > > codec_time_base=1/25
> > >
> > > codec_tag_string=tmcd
> > >
> > > codec_tag=0x64636d74
> > >
> > > id=N/A
> > >
> > > r_frame_rate=0/0
> > >
> > > avg_frame_rate=0/0
> > >
> > > time_base=1/50000
> > >
> > > start_pts=0
> > >
> > > start_time=0.000000
> > >
> > > duration_ts=192000
> > >
> > > duration=3.840000
> > >
> > > bit_rate=1600
> > >
> > > nb_frames=192
> > >
> > > nb_read_frames=N/A
> > >
> > > nb_read_packets=N/A
> > >
> > > DISPOSITION:default=0
> > >
> > > DISPOSITION:dub=0
> > >
> > > DISPOSITION:original=0
> > >
> > > DISPOSITION:comment=0
> > >
> > > DISPOSITION:lyrics=0
> > >
> > > DISPOSITION:karaoke=0
> > >
> > > DISPOSITION:forced=0
> > >
> > > DISPOSITION:hearing_impaired=0
> > >
> > > DISPOSITION:visual_impaired=0
> > >
> > > DISPOSITION:clean_effects=0
> > >
> > > DISPOSITION:attached_pic=0
> > >
> > > TAG:creation_time=2014-01-30 17:57:13
> > >
> > > TAG:language=eng
> > >
> > > TAG:timecode=11:54:27:03
> > >
> > > [/STREAM]
> > >
> > >
> > >
> > > How do I go beyond this to extract the full tmcd stream? 'ffprobe -i
> > > MVI_0006.MP4 -select_streams 2 -show_packets -show_data ' produces
> > output
> > > like:
> > >
> > > [PACKET]
> > >
> > > codec_type=data
> > >
> > > stream_index=2
> > >
> > > pts=191000
> > >
> > > pts_time=3.820000
> > >
> > > dts=191000
> > >
> > > dts_time=3.820000
> > >
> > > duration=1000
> > >
> > > duration_time=0.020000
> > >
> > > convergence_duration=N/A
> > >
> > > convergence_duration_time=N/A
> > >
> > > size=4
> > >
> > > pos=14832527
> > >
> > > flags=K
> > >
> > > data=
> > >
> > > 00000000: 0031 507d .1P}
> > >
> > >
> > >
> > > Is the '0031 507d' what I'm looking for, and if so, how to interpret
> that?
> > > Alternatively, if I'm barking up the wrong tree please point me to the
> > > right
> > > one!
> > >
> > >
> > >
> > > Many thanks,
> > >
> > > Francois
> > >
> > >
> > >
> > > Francois Visagie
> > >
> > >
> > >
> > >
> > >
> > > T: +27 (83) 326-4358
> > >
> > > F: +27 (86) 511-3490
> > >
> > > E: francois.visagie at gmail.com
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > ffmpeg-user mailing list
> > > ffmpeg-user at ffmpeg.org
> > > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> > >
> >
> > I don't think the data stream is what you need. Essentially you've
> already
> > got the timecode.
> >
> > TAG:timecode=11:54:27:03
> >
> > This gives you the starting time code of the first frame of your video.
> > This combined with the frame rate and video length is enough to set time
> > code for your entire file.
> >
>
> I'm aware of this approach and am considering it for other applications,
> but
> for this one it has some drawbacks. It requires additional steps to
> recreate
> the rest of the (existing) timecode stream, and mainly it cannot account
> for
> editing discontinuities. Thanks for the suggestion, though!
>
I don't think you can extract timecode to a single file without video.
You'd have to convert it to a more edit friendly video format like DNxHD or
ProRes and the timecode will go with it.
But I don't get the editing discontinuities part, you mean the mp4 file
that your camera creates is edited and has timecode jumps in it?
Doesn't it create a file per record-on/record-off button press?
Anyway I think you can get text output of timecode per frame by adding the
-show_frames option to the ffprobe command.
--
42
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