bsnes-hd (called "HD Mode 7 mod, for bsnes" in early betas) is a fork of bsnes (great SNES emulator by Near) that adds HD video features, such as:

HD Mode 7

Rendering the rotated, scaled or pseudo perspective backgrounds at higher resolutions. This does not involve new custom imagery or upscaling algorithms. It is a higher resolution version of the process the SNES uses.

• video comparison by reznoire (youtube)
• video demo by Emulators & Gameplay HD (youtube)

Widescreen

Extending the scenes to the left and right, without distorting them. Works for most Mode 7 scenes, but also for some other scenes/games, after some setting tweaking.

• Demo video: Chrono Trigger ending credits: Beyond Time by retroprez (youtube)
• Demo video: Chrono Trigger ending credits: Float Away by retroprez (youtube)

Objects/Sprites will not be visible correctly in the widescreen areas. Fixing this will require ROM-hacks. Some technical information is available below.

True color

Color calculation are done at true color instead of the SNES color depth (3x8 instead of 3x5 bit). With the optional line color smoothing color "steps" turn into actual gradients (without influencing the sharpness of the artwork).

Other high resolution features

Smother color gradients and window effect, not limited by the original resolution or integer precision.

plus some non-HD related features

like the ability to disable background layers, sprites and window effects for screenshots for wallpapers.