I realized this is an old thread, but rather than creating a new one on the same topic, I find it more appropriate to continue the same (paused) discussion.
Some question I picked up in the thread.
- How to easily merge several audio streams. (@NeilF)
- What to use for recording gaming footage. (@Sleep)
Merging of several audio streams, without recompressing the video footage.
Can be done using
ffmpeg, the swiss army knife of A/V transcoding.
It's
free and once you've tried it you tend to use it for anything that has to do with A/V post processing.
- You can use it to inspect what media streams are in your clip, to confirm whether or not you have many audio streams as you suspected, and what those streams are:
Code:
ffmpeg -i <my-video-file>
- You can use it to merge (mix) your audio streams while leaving your video alone.
Code:
ffmpeg -i source-clip.mp4 -c:v copy -filter_complex amix=inputs=2 -c:a libfdk_aac -b:a 384k mixed-clip.mp4
This basically says do a straight copy of the video stream, but mix two audio streams into one and then encode the mixed audio stream to AAC at 384 kbit, then store both video and audio in mixed-clip.mp4
See this awesome guide for all manner of channel mixing scenarios, and this one for merging *different* audio streams, like in the example provided. Possibly you had one or both of these kinds (several channels and several streams), and the ffmpeg probe/inspect command would inform you about the specific composition of your clip.
The great thing with a tool like this is that you can capture your footage in whatever format, frame rate and resolution you want and treat that capture as your raw source footage. Then you can adjust it to whatever medium and target is suitable. For example I always capture in 1920x1200 resolution at 60FPS and then I cut, reduce the frame rate, rescale, re-encode the audio or strip it altogether depending on the specific purpose of some media.
When submitting bug reports for ED, I downscale the video quite a lot, strip audio, reduce the frame rate to 30 or 15 FPS and then compress the footage *a lot*, to fit in the tiny 4MB file size slot that Frontier's defect submission page supports. When sending to youtube, I use another configuration to avoid Google doing any form of re-encoding. You get the point I hope.
How to record video footage
Well I'm no expert here, but I've tried quite a few variants and will summarize my experience.
- Fraps, Works flawlessly.
Keeps video and audio in sync, doesn't drop a frame (silk smooth playback), can manage high frame rates and is fairly very light on the CPU. Didn't notice any performance degradation at all in ED using a Core i7 4770 CPU and recording to an SSD. However the files are huge which is a trade off the developers did in order to achieve the low impact on the CPU. Final footage looks great and running it through ffmpeg afterwards produces stellar visual quality and small file size.
Verdict: Two thumbs up, worth every penny, but make sure you have a lot of SSD space.
- OSB, Works great for low FPS capture and keeps audio and video in sync.
Quicksync is a no-go with horrible performance. Software encoding with x264 is too slow for full HD at even 30 FPS. nVidia hardware encoder however works pretty well when recording at a low frame rate (30 FPS). At 60 FPS it starts to drop frames massively, both with the High Quality and High Performance settings, so I would only use it for full HD capture at 30 FPS and below. Seeing as most people capture for posting to Youtube, 30 FPS would be a perfect fit. The only downside is having to use the the hardware encoder on the graphics card, as such encoders are pretty bad from a quality perspective. I can definitely see the difference between a Fraps capture and using NVENC, but most gamers probably won't notice. On the plus side compared to Fraps, the disk space required is less per minute of captured footage.
Verdict: I give this one a thumbs-up for the casual video publisher, and it's free to boot.
- PlayClaw 5, Desynched audio and dropped frames. It did however produce fairly good image quality, small file size and was light on the CPU when using h264 nVidia hardware encoder. When using QuickSync (Intel HW encoder), it couldn't keep up with the 1920x1200 resolution at even 30 FPS so that option was a no-go. MJPEG produces larger files but fairly good picture quality, but also drops frames. The Desync of audio and video however was a deal breaker for me. That it drops a lot of frames for all encoders is also a big issue for me. So money down the drain is how I would rate this program in the currently released version of the package.
Verdict: Trashcan.
Note that it must be working working out for some people, as the program is getting fairly good reviews. None of the reviews however that I've come across have talked about how good the SW is at keeping audio in sync, and on the support forum for this software there is a slew of people having the same audio sync issues as I experienced.
- DXtory, got frame drops and audio desync.
Have read other people having more success though so I won't say it's junk.
Verdict: Trashcan for me personally.
- Virtualdub with VH Screen Capture Driver
Could not test as I have a 64 bit system, and SplitMedia (creator of the capture driver) doesn't offer a 64-bit version of their software.
If someone is still on 32-bit windows, this may be an option to explore, as I've had good results years ago with vdub and this driver on Windows XP.
Verdict: None (not tested)
To conclude, Fraps is just plain awesome. It's not free, but not expensive either, just $37. It does chew up quite a lot of disk space though. You also need fast disks, else you will get dropped frames. The software provided the smoothest frame rate of all SW tested, can capture at the highest FPS of all tested tools without dropping a single frame during the test, and the picture quality was also hands down the best.
OSB is the runner up. If money is tight and you only need 30 FPS captures, plus can live with a dropped frame here or there, use this one. You do need to have a modern video card with hardware video encoding for this to be a viable option. I tested using a nVidia GTX 780 graphics card and that card managed to keep 30 FPS 1920x1200 capture going with very few dropped frames. The audio was also in sync all the time which I consider paramount for any software in this space. The software is a little involved to configure initially (lots of buttons, switches and toggles), so if you're unfamiliar with video tech then ask a nerdy friend to help you out getting it setup, or if you have teenagers in the house, let them do it
