Hi all. I've been a long-term lurker and until now I haven't needed to post. Unfortunately that changed tonight when I attempted to remux an MPEG-TS file into an MKV. The path was a bit indirect but I eventually got there. Here's what I did:
Why the two-step? Well, mkvmerge threw errors when I gave it a ".mpeg" so I first had to get to an ".m2ts". That seemed to work, though mkvmerge did complain about additional bytes in the audio stream (and therefore gave a warning that the two might be out of sync). Here's the real question, though: Why is the MKV so much smaller than the M2TS? Check it out:
That's a reduction of almost 18% (from the MPEG) with no re-encoding or element conversion as far as I can tell. Is MKV just way more efficient or am I dropping something along the way? Here's Mediainfo output for each file:
General
ID : 255 (0xFF)
Complete name : C:\Video\Work\Camcorder\Tape 1.mpeg
Format : MPEG-TS Commercial name : HDV1080i File size : 11.1 GiB Duration : 1h 2mn
Start time : UTC 2008-02-01 01:00:24
End time : UTC 2008-06-07 12:55:58
Overall bit rate mode : Variable
Overall bit rate : 25.5 Mbps
Maximum Overall bit rate : 33.0 Mbps
Encoded date : UTC 2008-02-01 01:00:24
Video
ID : 2064 (0x810)
Menu ID : 100 (0x64)
Format : MPEG Video
Commercial name : HDV 1080i Format version : Version 2
Format profile : Main@High 1440
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : M=3, N=15
Codec ID : 2
Duration : 1h 2mn
Bit rate : 23.8 Mbps
Maximum bit rate : 25.0 Mbps
Width : 1 440 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9 Frame rate : 29.970 fps Standard : Component
Color space : YUV Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced Scan order : Top Field First Compression mode : Lossy
Bits/(Pixel*Frame) : 0.511
Stream size : 10.4 GiB (94%)
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio
ID : 2068 (0x814)
Menu ID : 100 (0x64)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : 3
Duration : 1h 2mn
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Delay relative to video : -181ms
Stream size : 172 MiB (2%)
Menu
ID : 129 (0x81)
Menu ID : 100 (0x64)
List : 2064 (0x810) (MPEG Video) / 2068 (0x814) (MPEG Audio) / 2069 (0x815) () / 2065 (0x811) ()
M2TS
----
General
ID : 1 (0x1)
Complete name : C:\Video\Work\Camcorder\Tape 1.m2ts
Format : BDAV Format/Info : Blu-ray Video
Commercial name : HDV 1080i
File size : 11.4 GiB
Duration : 1h 1mn
Overall bit rate mode : Variable
Overall bit rate : 26.6 Mbps
Maximum Overall bit rate : 35.5 Mbps
Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : MPEG Video
Commercial name : HDV 1080i
Format version : Version 2
Format profile : Main@High 1440
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : M=3, N=15
Codec ID : 2
Duration : 1h 1mn
Bit rate : 25.0 Mbps
Width : 1 440 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 29.970 fps Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.536
Stream size : 10.7 GiB (94%)
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : 4
Duration : 1h 1mn
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Delay relative to video : -296ms
Stream size : 168 MiB (1%)
MKV
---
General
Unique ID : 210217485311190726988062280093030469844 (0x9E266A3C180BD7D68F4E75AA1B58D0D4)
Complete name : C:\Video\Work\Camcorder\Tape 1.track_4113.mkv
Format : Matroska Format version : Version 4 / Version 2
File size : 9.15 GiB
Duration : 1h 0mn
Overall bit rate : 21.5 Mbps
Movie name : Tape 1
Encoded date : UTC 2013-09-18 23:34:56
Writing application : mkvmerge v6.4.1 ('Omega Point') built on Sep 16 2013 22:05:10
Writing library : libebml v1.3.0 + libmatroska v1.4.1
Video
ID : 1
Format : MPEG Video
Commercial name : HDV 1080i
Format version : Version 2
Format profile : Main@High 1440
Format settings, BVOP : No
Format settings, Matrix : Custom
Codec ID : V_MPEG2
Codec ID/Info : MPEG 1 or 2 Video
Duration : 1h 0mn
Bit rate : 20.7 Mbps
Maximum bit rate : 25.0 Mbps
Width : 1 440 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 fps
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.444
Time code of first frame : 00:00:00:00
Time code source : Group of pictures header
Stream size : 8.80 GiB (96%)
Title : Video
Language : English
Default : Yes
Forced : No
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio
ID : 2
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : A_MPEG/L2
Codec ID/Hint : MP2 Duration : 1h 0mn
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Delay relative to video : -67ms
Stream size : 167 MiB (2%)
Title : Audio
Language : English
Default : Yes
Forced : No
Thanks for any guidance!
Damon
P.S. Apologies if this is a re-post. I tried to post once before but it never showed up.
It's probably that the muxer uses less overhead to get the streams into the mkvcontainer.
I record .wtv (in my case mpeg2 files) and demux/remux them to .mpg and the file size gets larger - but there's no re-encoding taking place.
