FFMPEG - Convert M2TS file to MP4 or M4V while retaining TrueHD + AC3

[DavidFVancouver]

I wonder if some good folks online can help me out with my problem. I want to remux a .m2ts into a .mv4 (or .mp4) with the latest version of FFMPEG. From last years release of FFMPEG, I see TrueHD in a MP4 container is now supported. I want to mux (not transcode).

The file contains 2 streams, 1 Video, 1 Audio, the audio has AC3 fallback included “AC3 core + True-HD. Peak 5445Kbps (core 640Kbps) Sample Rate: 48KHz Channels 5.1”

The command is ffmpeg -i 00000.m2ts -strict -2 -c copy dex2.mp4.

The result is a smaller file 11.4Gb to 10.2Gb, and streams 3 is missing. This is the AC3 fallback. Does anyone know how to remux and combine the both the TrueHD and AC3 with fallback

I did read that MP4 has a limitation with multi audio streams, I could save as M4V, this supports multiply audio streams, but not sure how it will handle TrueHD.

I also notice a difference in bitrates if anyone has any comments there

Any Help will be very welcome


Original with from FFProbe

Input #0, mpegts, from '00001.m2ts':
Duration: 00:53:03.20, start: 4200.000000, bitrate: 29399 kb/s
Program 1
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc
Stream #0:1[0x1100]: Audio: truehd (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), s32 (24 bit)
Stream #0:2[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s


[Attachment 57229 - Click to enlarge]

The Result is 10.2GB from FFProbe

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'dex2.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.65.100
Duration: 00:53:03.18, start: 0.000000, bitrate: 26407 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 22953 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
Metadata:
handler_name : VideoHandler
vendor_id : [0][0][0][0]
Stream #0:1(und): Audio: truehd (mlpa / 0x61706C6D), 48000 Hz, 5.1(side), s32 (24 bit), 3408 kb/s (default)
Metadata:
handler_name : SoundHandler
vendor_id : [0][0][0][0]

[sneaker]

By default ffmpeg only maps 1 video, 1 audio and 1 subtitle track. If you want 2 audio tracks you need to map explicitly.

ffmpeg -i 00000.m2ts -map 0 -strict -2 -c copy dex2.mp4

Since ffprobe shows TrueHD and AC3 as separate tracks they should end up separately in the mp4 as well. I don't think ffmpeg (nor any other software) offers any feature to re-combine TrueHD and AC3.