CAPTURE BETTER PHONE AUDIO AND VIDEO
Darren Yates shares the basics as well as expert tips for getting the best results when shooting with your Android (and iPhone!) device.
Boost the quality of your audio and video recordings
Whether its recording uni lectures for easier note-taking or capturing a friend’s wedding for posterity, our phones have replaced so many devices we used to carry around – but that doesn’t mean you can’t improve your results. We’ve put together 15 of our best tips to boost the quality of your audio and video recordings, no matter what type of phone you have.
VIDEO TIPS
KNOW YOUR PORTRAIT AND LANDSCAPE
How you hold your phone when capturing video will make a big difference in how you best use that video later on. Hold it in the vertical or ‘portrait’ orientation and the video is probably best used for social media. But for more cinematic applications, rotate your phone and hold it in ‘landscape’ mode. Your PC, laptop and TV are all landscape-oriented devices, so it makes sense to maximum that screen area and shoot your videos in landscape mode. Your audience will love it.
USE MAXIMUM FRAME SIZE
To capture the best video your phone can muster, set the video frame size to the highest 16:9-aspect ratio option available. Many low-end phones may be limited to 1280x720-pixels, while mid-range phones usually reach 1920x1080-pixels. Top-drawer models will generally give you one or more ‘4K’ options. Using maximum frame size requires more storage space, even more battery life, but it’ll give you the maximum quality your phone has to offer. Remember – you can always reduce the quality of a video by shrinking the frame size after you’ve captured it. You can’t put the quality back again later if it’s not there to start with.
FIND A BETTER CAMERA APP
Android’s built-in Camera app does a fair job, but lacks user options, particularly for video bit rate. It’s one of those tricky parameters that affect not just the quality of the video you capture, but also the amount of storage your video needs, so not having the option to set the video bit rate is a problem. For example, the video bit rate for capturing 1,280x720-pixel video with the Camera app on a Samsung Galaxy A30 is 12.1-megabitsper-second (Mbps) – that’s 90MB of space per minute, which is excessive for that frame size. In contrast, YouTube needs only 3.5Mbps for high-quality 1,920x1080-pixel video. Open Camera is arguably the best camera app on Google Play – it’s free and puts you in the director’s chair, giving you control over many settings – including video bit rate. For longer captures, I’d shoot 1,280x720-pixel video at no more than 2Mbps, 1,920x1,080-pixel video at 5Mbps and 4K video at 10Mbps using H.264 compression, increasing those rates for shorter, more purposeful clips. In any case, Open Camera wins.
BE CAREFUL WITH DIGITAL ZOOM
It’s natural to want to zoom the lens to best frame your shot. The problem with most phones, however, is that digital zoom is often the only option and involves the phone using the centremost pixels of the image sensor and digitally magnifying them back up to the full frame size. Yes, it does zoom, but the more you zoom, the more pixels you’re throwing away, leaving fewer actual pixels with any real image data. In short, it’s sometimes called the ‘crop
and enlarge’ method of zoom. The result is an increasingly blocky video image the further you zoom in. However, Android phones are now starting to arrive with huge megapixel sensors – Xiaomi’s CC9 Pro phone has five image sensors, one of which packs in a massive 108-megapixels. These high-MP sensors have so many pixels that implementing digital zoom without the artefacts is fast becoming a possibility, although results are very much phone-dependent.
USE A TRIPOD
Once-in-a-lifetime moments won’t hang around while you muck about with a tripod, but these days, we’re capturing much more. The sensors in late-model phones are becoming good enough to knock out everything from interviews to training videos. Using a tripod is really the first rung up the video-quality ladder, but phones and tripods weren’t designed with each other in mind. Something like a Manfrotto Universal Smartphone Clamp solves that issue. It’s a springloaded clamp designed for smartphones up to 3.2-inches wide with two standard ¼-inch tripod screw-threads, one on the end and one on the back. For $20, it’s a neat solution. The clamp has silicon rubber grips to protect your phone and we had a Motorola Moto G5 clamped in for two hours doing training videos without any problems to the phone. If you’re shooting at desk level, budget mini camera tripods also start from $10.
GET YOUR DE-SHAKE ON
If a tripod is a no-go, it doesn’t mean you have to put up with video that bounces all over the shop. Post-capture video stabilisation or ‘deshaking’ mathematically corrects for individual frame movement, but it’s hard to do well and hard to do fast on a phone. That’s why it was such a shame Google killed off the video stabiliser enhancement from the YouTube Video Editor. However, there is an alternative – head to Google Play and search ‘Video Stabilizer’. Despite us saying phones aren’t ideally suited for video stabilisation, this app aims to do just that. User reviews are mixed, though, so try the free ‘trial’ version (20-second limit) and see if it works for you before spending $5 for the payware version. Adobe Premiere can also deshake video, but if you want a free PC alternative and you’re up for an
adventure, grab the old-school ‘VirtualDub’ video editor (virtualdub. org) and combine it with the exceptional (and equally complex) ‘Deshaker’ plugin (guthspot.se/video/ deshaker.htm). The results can be every bit as good as you could get from YouTube, although getting them is more difficult. Still, it’s free.
NO FILTERS, NO EFFECTS
This one will probably come down to personal taste, but our tip is don’t use filters or effects when shooting your videos because those filters and effects generally can’t be removed later. No doubt using a cats’ ears effect might have seemed like a good idea at the time, but you’re probably not going to use that video later for a job application for example. Grabbing as close to raw video as your device allows leaves you with a blank canvas to be creative with after the event. If you’re shooting for fun, by all means, go for your life and use whatever filters you like. But if you want to be able to re-use this video for different projects, start ‘raw’ and add in those tricks or treats in postprocessing instead. Put it another way – you can always add filters and effects later to a video, but you can’t take them out if they’re baked in already.
CLEAN THE LENS
This is a placeholder for all those things we forget to do before capturing video – like making sure the camera sensor panel is free of smeared finger-prints, charging up the phone battery before you shoot and making sure your phone has somewhere to store your takes. Its rumoured oldschool Hollywood filmmakers used to smear the camera lens (or a clear filter) with petroleum jelly to create a softer focus and give their subjects a more youthful look. You’d probably get a similar effect from smearing fingers covered in chip grease all over the sensor panel, but we’re pretty sure neither of these will do your phone much good. So, keep it clean using a glasses-cleaning cloth.
SHOOT WITH TWO PHONES
Why shoot with just one phone? Why not two? It’ll be harder to arrange those spur-of-the-moment videos, but if you’re creating something more planned like training or interview videos, a second camera angle can add more interest for your audience. You might be thinking who’d use a phone to shoot corporate videos clips, but it can be done (youtu.be/8YiwBsTQ_c0). Your phone won’t likely match a professional camera for video quality, but nor for price. The limiting factor in most phones is the image sensor itself, which is often tiny compared with those in even semi-professional video cameras. A small sensor limits your depth of field and low-light sensitivity. It also gives you a low ‘dynamic range’ between full brightness and complete darkness as the sensor sees it, which is also why phones often do their best work outdoors.
SOFTEN YOUR LIGHTING
On that note, good lighting is always key to capturing better-quality video. If you’re looking to use indoor video lights to brighten your subject, you probably want to avoid the typically harsh effect of sharply-defined shadow lines. Instead, using diffused lighting can give a more relaxed look. Video lights with diffusion boxes from photographic retailers usually aren’t cheap, but there are plenty of DIY ideas popular on online forums. For example, some users swear by grease-proof paper. It’s pretty good at diffusing light and you can increase the effect by simply adding more layers. However, although heat-resistance, it’s also pretty good at burning, being the flammable material it is, so treat this tip with extreme caution. Still, they don’t say ‘lights, camera, action!’ for nothing…
AUDIO TIPS FIND A BETTER RECORDER APP
Using your phone as an audio notetaker seems like an obvious idea, but it’s becoming a less common app in more new phones. Still, even when you do get an audio recorder app bundled in, it’s often a lacklustre affair. MP3 Recorder by Smart Mobile Tools is free on Google Play, offers capture in MP3 or WAV format, but importantly allows
“Don’t use filters or effects when shooting your videos because those filters and effects generally can’t be removed later”.
you to set the sample rate, number of channels, plus the audio bit rate. Hi-Q MP3 Recorder (payware) records WAV format as well, but gives you manual gain control. Both support stereo recording if your phone has two microphones.
AVOID AUTOMATIC GAIN CONTROL (AGC)
AGC became popular with audio cassette recorders in the 1970s, by doing away with the need to set audio levels manually – the recorder did it automatically, a bit like driving a car with an automatic transmission. The problem is that as the audio level falls (during quiet passages of music for example), AGC increases the amplification factor or ‘gain’ to compensate. If the gain is increased too far, you start hearing the electronics’ inherent background noise – the dreaded ‘hiss’. What’s more, as the audio levels change, this background hiss can rise and fall in intensity, which sounds distracting. For one-off notetaking, AGC is fine, but for more professional-sounding audio, look for apps that offer manual audio recording level control.
RECORD USING CD-LEVEL SAMPLE RATE
The full audio spectrum covers frequencies between 20Hz and 20kHz, but in order to capture this range, engineer Harry Nyquist discovered you need to digitally sample the audio at twice the highest frequency you wish to record. It’s one of the reasons why most music is sampled at 44.1kHz. It’s also a sample rate option offered in every phone today. You can record voice-grade audio (lectures, for example) using a lower sample rate, but much like capturing video at the highest frame resolution available, capturing audio at the highest sample rate uses more storage but ensures you get the highest quality audio your phone has to offer. You can always reduce this in post-processing.
CHOOSE AUDIO CODECS FORMAT CAREFULLY
Just as H.264 compression is important for storing large quantities of video on relatively small phone storage, audio compression formats or ‘codecs’, too, are important space savers.
For long recordings such as lectures, recording direct to a compressed format such as MP3, AAC, Vorbis or Opus can reduce your storage requirements down to as little as 240KB per minute using a 32-kilobitper-second (Kbps) bit rate and recording one channel (mono).
However, for maximum quality, use a lossless compression format or skip the compression altogether – 44.1kHz sample rate/16-bit WAV format is essentially CD-quality. It requires 317.5MB per hour per channel, but again, will capture the best your phone has to offer while keeping your options for any post-processing.
KNOW YOUR MICROPHONE
Smartphones use a type of microphone called ‘MEMS’ – Micro-ElectroMechanical Systems – to turn sound waves into electrical energy. Every microphone has a sound capture pattern called a ‘polar pattern’ that’s either ‘omni-directional’ (captures sound from any direction) or ‘cardioid’ (captures only a narrow angle). Many microphones are omni-directional, but even their ability to capture sound coming ‘off-axis’ (on an angle to its length axis) can be progressively dependent on frequency. The example polar pattern shows a traditional omni-mic – ‘0-degrees’ is sound captured from in front of the microphone along its length axis, ‘180-degrees’ is sound coming from behind. At a frequency of 1kHz or less, the ‘full circle’ pattern shows sound at this frequency is captured evenly from any direction. But at 8kHz, the microphone’s off-axis sensitivity is up to 10dB lower. Every microphone has a different pattern, but the principle is the same – point your phone’s microphone towards the source of sound you’re recording.