Ubuntu – Ffmpeg: can TS video be converted directly to MP4 video without re-coding

.mp4convertffmpegmkvvideo

I see here (How to convert .ts file into a mainstream format losslessly?) that MKV is recommended for that purpose (ffmpeg -i input -map 0 -c copy output.mkv), but not MP4, which is said to involve re-encoding the video.

(Based on that, I use sh -c 'ffmpeg -i "$0" -map 0 -c copy "${0%%.*}".mkv' %f in a context menu action as said here.)

Here (How to convert .mkv file into .mp4 file losslessly?) I see that converting MKV to MP4 without re-encoding is very easy (ffmpeg -i input.mkv -codec copy output.mp4), by simply changing the container.

If TS->MKV->MP4 conversion-without-recoding is possible, shouldn't TS->MP4 be possible directly too?

I have added to my file manager context menu the command sh -c 'ffmpeg -i "$0" -map 0 -c copy "${0%%.*}".mp4' %f and it works without problems for .ts files just like for .mkv .

Checking with Mediainfo the two resulting MP4 files (the TS->MP4 and the TS->MKV->MP4, where -> is the aforementioned command) I see basically the same info about their video content.

enter image description here

The rest is the same:

Encoding settings : cabac=1 / ref=1 /
deblock=1:0:0 / analyse=0x3:0x3 / me=dia / subme=3 / psy=1 /
psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0
/ 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 /
chroma_qp_offset=0 / threads=8 / lookahead_threads=2 /
sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0
/ constrained_intra=0 / bframes=3 / b_pyramid=0 / 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=0 /
rc=crf / mbtree=0 / crf=24.0 / qcomp=0.60 / qpmin=10 / qpmax=51 /
qpstep=4 / vbv_maxrate=3000 / vbv_bufsize=3000 / crf_max=0.0 /
nal_hrd=none / filler=0 / ip_ratio=0.71 / pb_ratio=1.30 / aq=1:1.00

Best Answer

TS > MP4? It Depends™

Yes, TS video be converted (re-muxed) directly to MP4 video without re-encoding if the video and audio formats are compatible. Your video is H.264 which is currently the most common and most compatible video format in MP4, so copying it from the TS to the MP4 will be no problem.

Arbitrary formats

TS supports more formats than MP4. If you try to mux arbitrary formats into MP4 the possible results are:

  • Success - the formats are supported by the FFmpeg MP4 muxer and your player/device.

  • Partial success - the formats are supported by the FFmpeg MP4 muxer, but not supported by your player/device. This could be the case for less common or legacy formats supported by MP4.

  • Failure - the formats are not supported and the muxer will give you an error message such as Could not find tag for codec foo in stream #0, codec not currently supported in container

Recommended procedure

So for full compatibility I recommend re-encoding if the formats are not the common and widely supported H.264 or H.265/HEVC video + AAC audio.

For automation you can use ffprobe to determine the formats. See Is there a way to use ffmpeg to determine the encoding of a file before transcoding? for an example. Then use an if/then statement in your script to execute the correct command.

Subtitles

The main exception is subtitles. MP4 doesn't have good subtitle support. If your TS contains text subtitles (ASS/SSA, SRT) then you can convert them to timed text (-c:s mov_text), but support for timed text subtitles among players is not universal. Image based subtitles will have to be excluded, such as with negative mapping -map 0 -map -0:s.

Related Question