Problem with joining 2 mkv files

[lascetic]

Hello, I've been trying to join two mkv files into one mkv, but the resulted file plays only the first part correctly and the second part is only audio and pixels.

I tried with both mkvtoolnix and avidemux but I get the same result. The two mkv files are encoded from 2 flv files with the same audio, aspect ratio and fps (only different video bitrate). The two mkv also have the same audio, aspect ratio and fps and I have tried both maintaining the initial video bitrates (from flv) and also encode them with exactly the same video bitrate. But they don't want to merge

I tried also joining the 2 FLVs into one flv (before encoding them into mkv) with avidemux but when I try to save the appended files avidemux says it supports only flv1 and vp6.

I tried also to use virtual dub but when I try to load the flv it says there is no video stream (?)

So, I ran out of ideas and thought to ask here.

I have windows 7 x64, latest versions of mkvtoolnix, avidemux, virtual dub and ffdshow and I used handbrake to turn the flv into mkv

[El Heggunte]

MediaInfo is not Google, therefore it's your friend

Please tell us what it says about those FOUR files (2 FLVs and 2 MKVs).

[lascetic]

General
Complete name : Part1.flv
Format : Flash Video
File size : 85.3 MiB
Duration : 14mn 23s
Overall bit rate : 828 Kbps
httphostheader : r7---sn-cg07luez.c.youtube.com

Video
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Format settings, GOP : M=1, N=50
Codec ID : 7
Duration : 14mn 23s
Bit rate : 691 Kbps
Width : 600 pixels
Height : 480 pixels
Display aspect ratio : 5:4
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.096
Stream size : 71.2 MiB (83%)

Audio
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 10
Duration : 14mn 23s
Bit rate : 129 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 13.3 MiB (16%)


General
Complete name : Part2.flv
Format : Flash Video
File size : 71.7 MiB
Duration : 15mn 27s
Overall bit rate : 649 Kbps
httphostheader : r5---sn-cg07luez.c.youtube.com

Video
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Format settings, GOP : M=1, N=50
Codec ID : 7
Duration : 15mn 27s
Bit rate : 512 Kbps
Width : 600 pixels
Height : 480 pixels
Display aspect ratio : 5:4
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.071
Stream size : 56.6 MiB (79%)

Audio
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 10
Duration : 15mn 27s
Bit rate : 129 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 14.2 MiB (20%)




General
Unique ID : 176455759026245649956609969871923384970 (0x84C0249CC01F51A518558EC8C5BF128A)
Complete name : Part1.mkv
Format : Matroska
Format version : Version 2
File size : 66.0 MiB
Duration : 14mn 18s
Overall bit rate : 644 Kbps
Writing application : HandBrake 0.9.9
Writing library : libmkv 0.6.5

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 14mn 18s
Bit rate : 512 Kbps
Width : 584 pixels
Height : 348 pixels
Display aspect ratio : 1.678
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.101
Stream size : 51.5 MiB (78%)
Writing library : x264 core 130 r2273 b3065e6
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=512 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / aq=1:1.00
Language : English
Default : Yes
Forced : No
Color primaries : BT.601 PAL
Transfer characteristics : BT.709
Matrix coefficients : BT.601

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 14mn 18s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 13.1 MiB (20%)
Default : Yes
Forced : No



General
Unique ID : 298668510556091661532119428742467475688 (0xE0B1767992985017E13DB53244AED8E8)
Complete name : Part2.mkv
Format : Matroska
Format version : Version 2
File size : 71.2 MiB
Duration : 15mn 27s
Overall bit rate : 644 Kbps
Writing application : HandBrake 0.9.9
Writing library : libmkv 0.6.5

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 5 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 15mn 27s
Bit rate : 512 Kbps
Width : 584 pixels
Height : 348 pixels
Display aspect ratio : 1.678
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.101
Stream size : 55.7 MiB (78%)
Writing library : x264 core 130 r2273 b3065e6
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=512 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / aq=1:1.00
Language : English
Default : Yes
Forced : No
Color primaries : BT.601 PAL
Transfer characteristics : BT.709
Matrix coefficients : BT.601

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 15mn 27s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 14.2 MiB (20%)
Default : Yes
Forced : No

[El Heggunte]

Hmmm, apparently there's nothing wrong with those MKVs

Anyway: What players have you tried? Does the problem happen in all of them?

And if MKVtoolnix gave you an error message, what did it say?

[lascetic]

I tried vlc, pot player, mpc and they all play only the first part while the second part is only audio and pixels.

mkvtoolnix didn't give an error message. It completed the process but the resulted file had the above problem. Exactly the same happened with avidemux when merging the mkv files.

The error messages (in avidemux and virtual dub) were only when I tried to join the flv files.

Is there any other reliable software that will join the flv files without changing their quality? Then maybe I can try and encode the joined flv into mkv.



Note: I just tried to save the joined flv into another form (mkv) with avidemux and it let me. But as I am not very familiar with the software, can anyone please tell me if the quality drops in this case? Here is the resulted technical specs:

Format : Matroska
Format version : Version 2
File size : 156 MiB
Duration : 29mn 51s
Overall bit rate : 729 Kbps
Writing application : Lavf54.63.104
Writing library : Lavf54.63.104

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.0
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Format settings, GOP : M=1, N=50
Codec ID : V_MPEG4/ISO/AVC
Duration : 29mn 51s
Width : 600 pixels
Height : 480 pixels
Display aspect ratio : 5:4
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Default : Yes
Forced : No

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : A_AAC
Duration : 29mn 51s
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Language : unknown
Default : Yes
Forced : No

[lascetic]

Apparently avidemux keeps the same quality for the joined flv even if it's saved as mkv (as long as audio and video outpout is set to "copy"). So I managed to join the files.

I just want to ask something more. I want to crop and re-encode the file into mkv but keep the quality as close to the initial quality, but the 2 initial files have different video bitrates (691 and 512). If I do a double pass with 691 kbps, I will probably end up with a larger file and 512 will drop the quality. Is there a workaround so I don't loose in quality but I don't end up with a larger file?

[videobruger]

There is no workaround. A re-encode will mean a loss in quality no matter what. If you want the same file size you'll need a bitrate of 605 kbps for the video part leaving the audio bitrate unaltered.

[lascetic]

OK, thank you (everyone) very much for your help.