Wedding Song Mix/Mashup

Job ID: 31325745

Budget: $30 – $250 USD

My fiancée and I are looking for a perfect song for our first dance, and have landed on a combination of our two favorite/most meaningful songs. I have "mixed" a very rudimentary example for you to understand what we're going for. We're looking for a significant improvement over this example, not simply volume adjustments, etc. Think key adjustments/matching, BPM matching, better transitions, using instruments from one song in the other so they flow better.

Requirements:
-Must use these two songs and arrangements (although you may add your own music to it)
--https://youtu.be/OCDpGe8r8Zo
--https://youtu.be/6cV_g1HgElg
-Must use 3 transitions minimum, as in the example (we don't want a simple "start with one song and transition to the other")
-Must begin and end with same songs (and same general song sections) as the example - we know exactly how we want to begin and end; you may be creative with when and where they are cut together
-Should be a reasonable song length, combined (e.g. example is 4:37)
-Should use (some) strings (as are prominent in "Can't Help...") in "Por Siempre..." and (some) piano (as is prominent in "Por Siempre...") in "Can't Help..." (unless otherwise agreed upon in advance)
-Otherwise, you should not stray too far from existing melodies, instruments, additions, etc. The end goal and what we will be happy with is a product that can successfully combine the two songs in a way that makes them seamlessly flow together and keeps the original feel.

Questions:
-How long do you expect to spend on this? (Total Hours)
-What are you ideas to improve over the example?