I am looking to professionally transfer recordings that have been recorded over the years via OTA antenna onto DirecTivo HD DVRs. I want to transfer them losslessly onto a very large computer hard drive. Compression is OK as long as it is lossless.
After emailing 2 of the local TV station engineers in my area, this is the path the videos have taken thus far: Original HD recording in Hollywood is uplinked in mp4 format to the CBS/ABC/NBC satellite -->downlink to local station as mp4 (4:2:2) -->OTA broadcast in 4:2:0 mpeg2 at 11.75 Mbps either in 1080i or 720p depending on the station -->recorded onto my DirecTivo HD DVR as mp4 -->HDMI output from the DVR -->video capture card on my new computer.
Knowing that the original recording has been compressed and uncompressed along the path to my DVR, how do I capture the video signal coming out of the DVR with the best possible quality and archive it losslessly (compression is OK)? Let’s assume HDCP is a non-issue. The DVR outputs 2 different audio tracks, 2 channel PCM and Digital Optical Out (5.1 channel Dolby Digital Surround Sound). I’d like to record them both with the video if possible.
My new computer specs are Intel chip i7-6950X Extreme 10 core with hyperthreading overclocked to 4.2GHz, 64 GB RAM (8x8 DDR4 2800MHz), video card 11GB NVIDIA GE Force 1080TI, 8TB HDD with RAID 1 mirroring, capable of expanding to max of 192 TB HDD, Windows 10 Home Edition.
Possibilities I’ve researched are:
Blackmagic IP4K ($199)
DeckLink Mini Recorder 4K ($195)
DeckLink Studio 4K 6G ($595)
DeckLink 4K Extreme 6G ($995)
DeckLink 4K Extreme 12G ($1495)
Are there companies other than Blackmagic Design that make high end video capture cards if I don’t mind “breaking the bank” to buy a card? For my purposes, are the higher end DeckLink models better in terms of recording? By better, I mean less buggy, less likely to have AV sync issues or dropped frames, less likely to do anything that will cause me frustration. Do I even need the higher end models, considering the video has already been lossy compressed and uncompressed a couple times on the way to my DVR? I’d also like to “future proof” my system a little bit by having it capable of recording 2160p30, because soon the H.265 encoder will allow the networks to broadcast in Ultra HD.
Is huffyuv the best codec for lossless compression? And what video editor do you recommend for my purposes: AVIsynth, FFMPEG, VirtualDub, OBS, DaVinci Resolve? Is the Blackmagic Media Express software any good? I don’t want to tinker with colors or anything fancy, just record and archive the original broadcasts.
What do you guys recommend for capture card, codec, video editor and anything else I might need?
And finally, as an afterthought, are any capture cards capable of capturing/recording two video streams at the same time, and if so, would my computer be capable of handling that?
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I have not seen any "lossless" HDMI capture cards which which allow capturing multi-channel audio via TOSLINK (optical audio out). They use HDMI as the digital audio source instead.
Magewell is a new company which is estabishing a reputation for making quality professional capture products. You might want to look at this device as well:
Audio capture with the Magewell Pro Capture HDMI is limited to 2-channels stereo when capturing video with any of the supported software. (The audio source is HDMI.) You would probably need to write your own software to capture video and multi-channel audio simultaneously. According to a post written by someone here who owns the Magewell Pro Capture HDMI, he was only able to capture multi-channel audio using sample code provided in the SDK, but the sample code doesn't capture video at the same time. I don't remember if the capture source was 5.1 channel LPCM audio or 5.1 channel AC3 audio.
I don't recall anybody here posting about any attempts (successful or otherwise) to capture 2 hdmi sources at once, applying lossless compression. For what it's worth there is a Magewell card with dual HDMI inputs: http://www.magewell.com/pro-capture-dual-hdmi
HuffyUV is used by many of this forum's members, but Ut Video and MagicYUV are faster.
Last edited by usually_quiet; 18th May 2017 at 12:59. Reason: clarityIgnore list: hello_hello, tried
If you don't know this already, your lossless HD captures are going to be pretty massive and in the 100GB range per hour.
usually_quiet, that's a little disappointing 2 audio tracks can't be captured on the same video recording in this day and age. But obviously it's doable if it's recorded onto the DVR that way. Or is it only possible with lossy compression?
My concern about Magewell is that Chinese companies have a reputation for poor tech support. Have you had issues with the Blackmagic Design products? And what video editor do you like and why?
KarMa, 100s of GB/hr AFTER lossless compression?
Most video capture devices can only capture stereo audio. Popular capture software has similar restrictions on account of the hardware restrictions. Several requests for capture cards/devices capable of capturing 5.1 channel (and higher) digital audio have been posted here in the past few years, but I can recall no recommendations were provided except for the small number Hauppauge capture cards and USB capture devices which support recording bitstreamed AC3 audio as is.
I use VideoReDo TV Suite 5 --which is not something I would recommend for working with lossless captures. It is really great for editing transport streams.
Last edited by usually_quiet; 18th May 2017 at 15:51.Ignore list: hello_hello, tried
So it seems like I'm stuck with
2 channel sound + lossless video OR
the choice of 5.1 or 2 ch sound + compressed video
Is that correct?
What kind of color subsampling would I need in the capture card? The OTA network broadcast is MPEG-2 at 4:2:0, but it is encoded into my DVR as mp4 by who knows what kind of encoder inside the DirecTivo DVR box. Does anyone know what kind of color subsampling would come out of such a box? If it's still 4:2:0, is there any reason for me to pay big bucks for a video capture card that records in 4:4:4?
Anyone else like to weigh in on their favorite capture card, codec or video editor and why they like it?
Ignore list: hello_hello, tried
If the channels you tend to record are also available locally OTA, like NBC/CBS/ABC/FOX, then you can easy record the original MPEG2 broadcast via an antenna to your computer and decode it as you wish, since OTA is not encrypted (pay satellite is encrypted). Which would be a "lossless" recording of the original broadcast for 3-5GB per hour in MPEG2, which pretty much anything can decode.
As far as losslessly recording your DVR videos, you would use 4:2:0 as the content is already 4:2:0 and anything higher would be just a bigger filesize for zero gain. Those 4:4:4 captures I guess would be more geared toward content producers who have cameras with 4:4:4 output and wish to record that. Anything other than 4:2:0 is pretty much unheard of for consumer level TV programing, on both OTA and pay satellite tv. However I know that it's common for TV networks to transmit H.264 4:2:2 to their affiliates over satellite, which is then downsampled to 4:2:0 and re-encoded to MPEG2 for OTA. Downsampling to 4:2:0 would be true for any DirectTV feeds to paying customers.
Wow, thanks for those great detailed answers, guys!
usually_quiet, I think you are spot on correct about the OTA recordings actually being MPEG-2. I just assumed they were h.264 ("mp4"), because, as KarMa says a few years ago DirecTV switched to what THEY call MPEG-4 (actually h.264).
karMa, thank you for that detailed breakdown. It was very educational. To clarify, the recordings actually are OTA broadcasts, not DirecTV broadcasts. I have an AM21 OTA Tuner that feeds into the DirecTivo box and so I have my choice of recording the local broadcast from OTA or satellite. In fact, I specifically posed that question to the 2 station engineers. Both said the OTA would be better quality because "DirecTV reencodes our OTA MPEG2 stream into MPEG4."
Quote from KarMa: " However I know that it's common for TV networks to transmit H.264 4:2:2 to their affiliates over satellite, which is then downsampled to 4:2:0 and re-encoded to MPEG2 for OTA." Again, spot on correct. That is EXACTLY what the engineers for our local ABC and CBS affilliates told me.
So these recordings are most likely MPEG-2 then. Are you telling me that means that using lossless compression, I will only use 3-5 GB/hr of HDD space as opposed to 100GB/hr? I'm still a little unclear as to what type of recording would use 100 GB/hr.
And while we're on the subject, will the write speed of 6GB/s on my Seagate 8TB BarraCuda Pro 7200RPM SATA 6Gb/s 256MB Cache 3.5-Inch Internal HDDs in RAID 1 (mirroring) configuration be fast enough to keep up with the stream?
Anyone out there have any experience with the Blackmagic Design Decklink models? How well they work, if they're buggy, will they record 5.1 audio?
I inadvertently discovered its multichannel audio capability...while recording a live internet video stream that delivered 5.1 audio.
I played back the recording on my computer, and various parts of the video were missing certain dialog & sounds.
Then it hit me. In the capture card properties, it displayed all the channels of audio.
But no matter what recording software I used (MageWell, OBS, XSplit)...they are all limited to recording 2 channel audio.
Like the quoted user says, the card has the capability...and there's a little app for recording multichannel audio...but it's useless unless you can time the video & audio to record at the same time.
The OP mentioned Magewell being a Chinese company with possibly poor tech support.
Well, here's my experience.
- BEFORE I purchased, I sent them an email about VCR capturing which never got answered.
- But AFTER I purchased, I could enter my product serial number in the support field: They replied to me within 24 hours...and they've kept replying to my inane follow-ups without a hint of frustration. I'm impressed.
For example, I pivoted from asking about PAL/NTSC option...to how to get the card working with Adobe Premiere.
This is a completely unofficial thing & not supported...but the Chinese support guy's great. He's giving me unreleased beta software & plugins, and holding my hand until it works.
The DirecTV AM21 OTA tuner is an accessory for DirecTV's HR21 through HR23 HD DVRs. You don't actually have a "DirecTiVo".
"DirecTiVo" was the name given to a couple of older genuine TiVo models. They were much like the Series 1 and Series 2 TiVos, but equipped with an integrated DirecTV receiver for DirecTV subscribers.
Ignore list: hello_hello, tried
Connecting to everything from an HDMI-enabled camera to an HD-SDI VTR, KONA LHi offers a full host of no-compromise features, including 10-bit or 8-bit uncompressed video, 2-channel AES digital audio and 8-channel SDI embedded digital audio, analog composite or S-video or SD/HD component video I/O, and 2-channel balanced analog audio I/O.
• 8-Channel, 16- and 24-bit SMPTE-259 SDI embedded audio, 48 kHz sample rate, synchronous
• 8-Channel, 16- and 24-bit HDMI embedded audio, 48 kHz sample rate, synchronous
• 2-Channel, 16- and 24-bit AES/EBU audio, 48 kHz sample rate, synchronous or nonsynchronous, internal sample rate conversion (via 1 x XLR on breakout cable or optional KLHi-Box)
Last edited by usually_quiet; 19th May 2017 at 11:09.Ignore list: hello_hello, tried
Whew! Quite a bit to digest here. I was also looking at the Aja KONA site this morning. It seems to open up a whole world of possibilities. So do we think it is possible to record both a 5.1 ch and a 2 ch PCM stereo track on these high end Aja devices with the same video stream? Also the only TOSLINK to HDMI audio converters I found all downsample from 5.1 ch to 2 ch. Is HDMI only capable of carrying 2ch audio? If so, is there a workaround to get 5.1 recorded using any of the other Aja KONA audio inputs?
usually_quiet: Yes, to be specific, most of my recordings are on THR22 devices although some of the older ones are on HR10-250 devices. Not sure I understand in your last post if 2 separate audio tracks might be a possibility with the Aja KONO line?
KarMa: I'm still a little unsure what you are referring to as recording at 3-5GB/hr?
vaporeon800: I've quietly read lots and lots of your posts over the years. You seem to be incredibly knowledgeable and experienced re the Blackmagic products. Any input on if they'd accomplish what I'm trying to do? Or if their Decklink models would?
The KONA LHi accepts 8 channels of audio through HDMI. See https://www.aja.com/products/kona-lhi#techspecs. I think you will have a very hard time finding a device that accepts stereo and 5.1 digital streams at the same time. Why do you need to do that anyway? Surround sound can be mixed down to stereo on the fly by most players.
I prefer Lagarith for the higher compression. Even better compression is afforded by FFmpeg's FFV1 lossless codec.
Wanting to record from two audio connections on your satellite receiver at one time makes no sense to me. They will all be derived from a single audio stream in the broadcast (i.e. English, Spanish, or Descriptive Video Service (DVS)) selected by the user. As pointed out, 5.1 channel audio can be down-sampled.
Last edited by usually_quiet; 19th May 2017 at 14:50. Reason: grammarIgnore list: hello_hello, tried
JVRaines: Thanks for all your great info. It is much appreciated. Would you be able to point me to a TOSLINK to HDMI converter that leaves the 6 channels of 5.1 alone and doesn't downconvert them to 2 channels?
These OTA Broadcasts are Transport Streams (.ts) and can be recorded easily with a cheap tuner card and a standard antenna, allowing for simple recording and simple decoding on your computer. No encryption happens with OTA Broadcasts, so none of this lossless capture headache is required, unlike pay satellite tv and just about all digital cable tv providers. So if you are recording your local NBC/CBS/ABC/FOX/PBS channels then you may want to just get an antenna and a cheap tuner card to record these channels, giving you access to the original MPEG2 video without encryption. Also without any possibility of having your DVR re-encode it to H.264, which would degrade quality if the DVR is really doing that.
I personally record my local OTA channels using a antenna and an older HVR-1250 tuner card, which gives the the broadcast .TS containing the original MPEG2. There is nothing very special about my card other than I use it also for capturing analog VHS too. To my knowledge the USB equivalents used for Tuning into ATSC OTA are pretty good these days and you probably don't need an internal card if you don't want one. So USB or Internal card is up to you. The WinTV software that came with my Hauppauge card is alright and is used for scheduling recordings or doing live watching but I tend to like Windows Media Center that comes with Windows 7, something which Windows discontinued.
Lagarith having probably the best realtime (SD realtime) compression ratios and FFV1 having even better ratios but requires a longer encode time (not realtime).
Just did a few tests and I estimate uncompressed 1080p @30fps 8-bit YV12 (4:2:0), to be around 746Mbit per second (300GB per hour). This is what these 8-15Mbit OTA broadcasts get decoded to by the tuner/decoder in the TV, which is then displayed on the TV. This is why lossy compression is a thing and makes our modern television/streaming possible. For lossless HD capturing you will probably need to use a faster codec than Lagarith or FFV1, so something like Ut Video or x264 (ultra fast lossless preset) would be able to get that down to around 210Mbit (90GB per hour) at least in my tests in real time. Also can do HUFFYUV or MagicYUV options too for faster encoding.
JV Raines: thanks so much for the link and search terms. I've never heard of an HDMI injector until now. Have you heard of them causing any A-V sync issues or sound quality degradation?
KarMa: I've been studying your post for about the past two hours now, going back & forth to Wikipedia for explanations of transport streams, MPEG, uncompressed video etc. What I'm having trouble grasping is this. Let's say you & usually_quiet record the NBC MPEG-2 OTA transport stream broadcast of Saturday Night Live tomorrow night from your OTA antenna/tuner card/Hauppauge set ups and it costs you 3-5 GB/hr. I get up Sunday morning a few hours later, play it out of my DVR's HDMI port onto a high end video capture card and it costs me 300 GB/hr. AND you two get a better quality recording than I do! Why? What part am I missing here?
And are you guys recording 5.1 ch sound on your transport stream recordings?
If you capture the HDMI video losslessly you will have the same quality video as they do (assuming equal quality decoders), but it will be much larger. You can't get back the 5.1 audio.
Last edited by jagabo; 19th May 2017 at 20:07.
OK, thanks jagabo for the explanation. I don't suppose there's any way to go into the box and just pluck those OTA MPEG-2 files away from the DirecTV content Nazis, is there? I'm assuming that, even though it's an OTA recording, it's still encrypted on the box with a key no one has been able to break yet. Is that correct?
Regarding the 5.1 audio though, If I understand the concept correctly, I would still be able to capture that on a video capture card via a TOSLINK to HDMI converter as mentioned above in JVRaines post, right? There is a digital optical audio out port on the back of the DVR.
As far as capturing 2160p goes, current devices used for commercial video (i.e. Netflix 4K, UHD Blu-ray) supply 2160p60 output. These devices must be equipped with HDMI 2.0, which applies HDCP 2.2 encryption (harder to defeat than HDCP 1.3). ...and HDMI 2.1 is coming. Since the future is still a bit fuzzy, I would not worry about future-proofing.
Last edited by usually_quiet; 19th May 2017 at 21:49. Reason: clarityIgnore list: hello_hello, tried
usually_quiet and KarMa: I just dug my old Hauppauge Colossus out of the closet. I had used it years ago to capture some music performances coming out of the HDMI output on my DirectTV DVR, much like I plan on doing now. Although there were a few hitches and dropped frames here and there, it was fine for my purposes then, but now I want archival quality. I was using it then to make lossy compressed h.264 files. It sounds like you are using it (or some similar Hauppauge product) but in a different manner to directly record OTA MPEG-2 broadcasts live. Is is possible for me to use the Hauppauge Colossus for this purpose going forward?
Before I bought the HDHomerun Prime, I used a Hauppauge HD-PVR Colossus to record both video and 5.1 AC3 audio via HDMI-out from my cable box. The Colossus has no tuner and is incapable of allowing users to record OTA TV broadcast transport streams from an antenna connection like the Hauppauge WinTV-HVR-2250 can.Ignore list: hello_hello, tried
How can I tell which players are capable of converting/downsampling 5.1 ch to 2 ch sound? Could anyone give me a couple examples or point me where to look re this?
Is there any degradation in audio quality by doing the 5.1ch-->2ch conversion versus recording the 2ch directly?
And if I record the OTA MPEG 2 transport stream directly onto the computer from a tuner like the Hauppauge HVR-2250 (or something similar), I will automatically be recording BOTH the 5.1ch and 2 ch audio. Is that correct?
Is the two-channel audio you are concerned about recording the two-channel audio available from HDMI, with 5.1 channel audio being available simultaneously via TOSLINK? If so, the 2-channel HDMI audio isn't present in the broadcast. The satellite box is down-sampling from 5.1 channels in the recorded broadcast to 2 channels for HDMI output.Ignore list: hello_hello, tried