why with two almost identical files, only one gets transcode

[smoker]

Hi, in my setup, low end pc, shitty network, I am trying to only play content where no transcoding is necesary.
So in trying to understand when the server transcode or not, I downloaded almost 2 identical files.
File1 gets transcoded, thus doesnt play well in my setup, File2 doesnt get transcoded, so plays well.
Could someone explain to me why this is? (details of file hereunder)
THX!

##File1##
General
Complete name : F:\LOST.S05E06.720p.HDTV.AC3.AVC-GB\glftpd\site\torrents\nosebleed\LOST.S05E06.720p.HDTV.AC3.AVC-GB\LOST.S05E06.720p.HDTV.AC3.AVC-GB.mkv
Format : Matroska
File size : 1.32 GiB
Duration : 41mn 55s
Overall bit rate : 4 496 Kbps
Encoded date : UTC 2009-02-19 09:23:28
Writing application : mkvmerge v2.4.2 ('Oh My God') built on Jan 18 2009 17:30:28
Writing library : libebml v0.7.7 + libmatroska v0.8.1

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Muxing mode : Container profile=Unknown@3.1
Codec ID : V_MPEG4/ISO/AVC
Duration : 41mn 52s
Bit rate : 4 117 Kbps
Nominal bit rate : 4 300 Kbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16/9
Frame rate : 23.976 fps
Resolution : 24 bits
Colorimetry : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 0.186
Writing library : x264 core 66 r1109M 75b495f
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=6 / psy_rd=1.0:0.0 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / chroma_qp_offset=-2 / threads=6 / nr=0 / decimate=1 / mbaff=0 / bframes=3 / b_pyramid=1 / b_adapt=1 / b_bias=0 / direct=1 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=2pass / bitrate=4300 / ratetol=1.0 / qcomp=0.60 / qpmin=1 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Codec ID : A_AC3
Duration : 41mn 55s
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Channel positions : L R
Sampling rate : 48.0 KHz



##File2##
General
ID : 1
Complete name : E:\download20090224\lost.s05.e06.720p.hdtv.Ps3.Nlsubs.mpg
Format : MPEG-TS
File size : 1.14 GiB
Duration : 41mn 53s
Overall bit rate : 3 895 Kbps
Maximum Overall bit rate : 35.5 Mbps

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Duration : 41mn 51s
Bit rate : 3 356 Kbps
Nominal bit rate : 3 346 Kbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16/9
Frame rate : 23.976 fps
Resolution : 24 bits
Colorimetry : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 0.152
Writing library : x264 core 65 r1047 f773bf0
Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x111 / me=dia / subme=5 / psy_rd=0.0:0.0 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / chroma_qp_offset=0 / threads=3 / nr=0 / decimate=1 / mbaff=0 / bframes=16 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=3 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40(pre) / rc=cbr / bitrate=3346 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / vbv_maxrate=40000 / vbv_bufsize=40000 / ip_ratio=1.10 / pb_ratio=1.10 / aq=1:1.0

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Duration : 41mn 53s
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz

[shagrath]

it's due to the different containers...one is mkv (who need transcode, by default), the other one is mpeg (who do not need transcode, by default)
but all these should be seamlessly streamed (and not transcoded) with the next version

[ExSport]

Or moving tsMuxeR as first "transcoder" will do same, muxing will be used as default