How can I tell what glowy-ring buffs the enemy team currently has?

To my knowledge, all the following buffs have identical effects of glowing rings around the players' feet, as shown in this picture:

• Deploying a Buff Banner
• Deploying a Battalion's Backup
• Deploying a Concheror
• Playing a medicating melody with the Amputator
• Deploying Ubercharge with a quick-fix

If I could not see the source soldier/medic, what are some tell-tale signs I could easily/instantly recognize their buffs? Additionally, if I saw a buffed soldier coming in from a distance, how can I distinguish what his buff is?

Solution 1:

The auras given by the Soldier's banner buffs have these color schemes:

• RED: golden-yellow glow
• BLU: cyan-aquamarine glow

Whereas the auras given by the Medicating Melody or Quick-Fix ÜberCharge are standard red and blue in color respectively.

A player being buffed by the Buff Banner will have a weapon glowing the same color as the aura, so a RED player for example will have both a golden-yellow aura and a golden-yellow weapon. A player being buffed by the other banners won't have a glowing weapon.

Telling a Battalion's Backup buff from a Concheror buff is more difficult: if you're looking at the Soldier who deployed the banner, he'll be carrying a different flag; see Retrosaur's answer for what the banners look like. However, if he isn't visible, you won't be able to tell which of the two buffs his teammates have received unless you heard the horn, or until you engage them in battle.

The difference between a Medicating Melody and a Quick-Fix ÜberCharge is that the latter will also shower the Medic and his patient with sprinkling healing crosses, not to mention the presence of a healing beam.

From what I've observed, all auras pulsate at the same frequency.

Solution 2:

In addition to other answers here, an easy way to tell which buffs are deployed by Soldiers are the flags that are being deployed.

Buff Banner:

The war flag itself – which is rectangular and colored faded yellow with a brown starbust design and moves realistically – remains hidden in the backpack until it is activated, at which point it will appear on a pole mounted to the pack.

Battalion's Backup:

...a tattered yellow triangular banner, patched up and reattached in the middle, that is displayed when the buff is active

The Concheror

A white, slightly tattered, vertical banner flag with the same diamond insignia secured onto a pair of bamboo sticks appears when the banner call is played.

If your computer has higher graphic settings, and you can see enemies from far away, sometimes the horns are a good giveaway, indicated by either a brass trumpet (Buff Banner), a brown horn (Battalion's Backup), or a white Seashell (Concheror).