[FFmpeg-user] Can't concat Garmin DashCam videos with telemetry (GPS data)

[William C Bonner]

On Fri, Jul 30, 2021 at 3:47 PM William C Bonner <wbonner at wimsworld.com>
wrote:

> On Wed, Jul 28, 2021 at 3:15 PM Suporte JM <jmgeosuporte at gmail.com> wrote:
>
>> Hi,
>>
>> I have a Garmin 66W dashcam for my work (street mapping surveyor) which
>> produces several 1min. MP4 videos of my journey (60 min. = 60 videos). All
>> these videos have telemetry data on it as metadata (GPS location, speed,
>> etc...).
>>
>> I want to concatenate every 5 files excluding the audio but preserving the
>> video and the telemetry in the metadata.
>>
>> What I have tried so far:
>>
>>
>>    - Export GPS information as GPX file (result: successful)
>>
>> *exiftool -p gpx.fmt -ee X:\video_place\videos_1m\GRMN0005.mp4 >
>> GRMN0005.gpx*
>>
>>
>>    - Merge MP4 videos as a single MP4 video (result: partially successful)
>>
>> *ffmpeg -f concat -safe 0 -i X:\video_place\videos_1m\mylist.txt -c copy
>> X:\video_place\videos_1m\GRMN0005to0011.mp4*
>>
>> When I use the above command on ffmpeg *I lose all my telemetry data*.
>>
>> I tried in several different ways for days, searching on several forums, I
>> even tried to export all GPS data from each single 1min. file merge them,
>> and then merge the videos and put the telemetry back.
>>
>> The ffprobe output of my 1min. video is as following:
>>
>>
>> *Metadata:major_brand : avc1minor_version : 0compatible_brands:
>> avc1isomcreation_time : 2021-07-26T17:08:23.000000ZDuration: 00:01:00.06,
>> start: 0.000000, bitrate: 19553 kb/sStream #0:0(eng): Video: h264 (Main)
>> (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 19182 kb/s, 29.97 fps,
>> 29.97 tbr, 30k tbn (default)Metadata:creation_time :
>> 2021-07-26T17:08:23.000000Zhandler_name : Ambarella AVCvendor_id :
>> [0][0][0][0]encoder : Ambarella AVC encoderStream #0:1(eng): Audio: aac
>> (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 128 kb/s
>> (default)Metadata:creation_time : 2021-07-26T17:08:23.000000Zhandler_name
>> :
>> Ambarella AACvendor_id : [0][0][0][0]Stream #0:2(eng): Subtitle: mov_text
>> (text / 0x74786574), 0 kb/s (default)Metadata:creation_time :
>> 2021-07-26T17:08:23.000000Zhandler_name : Ambarella EXT*
>>
>> I have tried as well with following code, but none of them seems to work:
>>
>>
>> *ffmpeg -f concat -safe 0 -i X:\video_place\videos_1m\mylist.txt -c copy
>> -scodec copy X:\video_place\videos_1m\GRMN0005to0011_scodec.mp4*
>>
>>
>> *ffmpeg -f concat -safe 0 -i X:\video_place\videos_1m\mylist.txt -c:s copy
>> -c:v copy X:\video_place\videos_1m\GRMN0005to0011.mp4*
>>
>> *ffmpeg -f concat -safe 0 -i X:\video_place\videos_1m\mylist.txt -c copy
>> -c:s mov_text X:\video_place\videos_1m\GRMN0005to0011.mp4*
>>
>> What am I missing?
>>
>
> I don't know if this will help, but I have a program I wrote that uses
> ffmpeg to concatenate the output files from my drone and embed the subtitle
> files that are created for each input mp4 file. I'm creating MKV files,
> because they are the most flexible video storage format that I've found.
>
> I create two temporary files for the input, the first is the list of the
> MP4 files, the second the list of SRT files.
>
> ffmpeg.exe -hide_banner -f concat -safe 0 -i
> C:\Users\Wim\AppData\Local\Temp\WimF5FC.tmp -f concat -safe 0 -i
> C:\Users\Wim\AppData\Local\Temp\WimF5FD.tmp -map 0:v -map 1 -c:v copy -c:s
> copy -movflags +faststart -n 20210718.mkv
>
> The nice thing that I figured out is that the SRT files get added at the
> correct point in the output file, and I can run the following command to
> extract a copy of the SRT that's been embedded, and I see the timestamps
> are correct for the full concatenated file.
>
> ffmpeg.exe -hide_banner -n -i 20210718.mkv 20210718.srt
>
>
I remembered another trick that I'd run into when converting DVD rips to
h.264 but keeping all the subtitle or audio tracks from the original. It
has to do with the -map 0 option.

Try this version of your command:

ffmpeg -f concat -safe 0 -i X:\video_place\videos_1m\mylist.txt -c:v copy
-c:a copy -c:s copy -map 0  X:\video_place\videos_1m\GRMN0005to0011.mp4