## Scatter Plots: MUSHRA Scores vs. Bitrate Across Three Bitrate Ranges ### Overview The image contains three scatter plots comparing audio codec performance (MUSHRA scores) across low, medium, and high bitrate ranges. Each plot uses bitrate (kbps) on the x-axis and MUSHRA scores (0-100) on the y-axis. Five codecs are compared: SoundStream, SoundStream - scalable, EVS, Opus, and Lyra. ### Components/Axes - **X-axis (Bitrate)**: - (a) Low bitrate: 3–12 kbps - (b) Medium bitrate: 6–15 kbps - (c) High bitrate: 12–21 kbps - **Y-axis (MUSHRA Score)**: 20–80 across all plots - **Legend**: - SoundStream: Blue diamond - SoundStream - scalable: Blue circle - EVS: Green diamond - Opus: Orange star - Lyra: Gray triangle ### Detailed Analysis #### (a) Low Bitrate (3–12 kbps) - **SoundStream**: 6 kbps, ~70 score (blue diamond) - **SoundStream - scalable**: 6 kbps, ~65 score (blue circle) - **EVS**: 6 kbps, ~50 score (green diamond) - **Opus**: 12 kbps, ~60 score (orange star) - **Lyra**: 3 kbps, ~30 score (gray triangle) #### (b) Medium Bitrate (6–15 kbps) - **SoundStream**: 9 kbps, ~80 score (blue diamond) - **SoundStream - scalable**: 9 kbps, ~75 score (blue circle) - **EVS**: 9 kbps, ~45 score (green diamond) - **Opus**: 15 kbps, ~80 score (orange star) #### (c) High Bitrate (12–21 kbps) - **SoundStream**: 12 kbps, ~85 score (blue diamond) - **SoundStream - scalable**: 12 kbps, ~80 score (blue circle) - **EVS**: 15 kbps, ~70 score (green diamond) - **Opus**: 21 kbps, ~80 score (orange star) ### Key Observations 1. **SoundStream** consistently achieves the highest scores across all bitrates, with a notable peak at 85 in high bitrate. 2. **Opus** performs strongly at higher bitrates (80 in medium/high) but lags behind SoundStream in low bitrate. 3. **EVS** shows the lowest scores in low/medium bitrates (~45–50) but improves to ~70 in high bitrate. 4. **SoundStream - scalable** underperforms its non-scalable counterpart in low/medium bitrates but matches it in high bitrate. 5. **Lyra** is only tested at 3 kbps with the lowest score (~30), suggesting poor performance at ultra-low bitrates. ### Interpretation - **Efficiency Trends**: SoundStream and Opus demonstrate superior efficiency, maintaining high scores even at lower bitrates. EVS requires higher bitrates to achieve competitive performance. - **Scalability Impact**: The scalable version of SoundStream loses ~5 points in low/medium bitrates but converges with the non-scalable version at high bitrates, suggesting scalability trade-offs at lower bitrates. - **Lyra's Outlier**: Lyra's inclusion only in low bitrate with a score of ~30 highlights its unsuitability for higher-quality applications, even at minimal compression. - **Bitrate-Quality Relationship**: Higher bitrates generally improve MUSHRA scores, but codec choice significantly influences outcomes. SoundStream and Opus outperform others across the spectrum, while EVS and Lyra require higher bitrates to compete. This analysis underscores the importance of codec selection based on bitrate constraints and quality requirements. SoundStream emerges as the most robust performer, while EVS and Lyra show context-dependent limitations.