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05395205dd
Fixes #12028 There was an additional issue that audio was always delayed by half the configured search-interval. This was caused by the `out` buffer length not being included in the delay calculation. Notes: - Every WSOLA iteration advances the input buffer by _some amount_, and produces data in the output buffer always of size `ola_hop_size`. - `mp_scaletempo2_fill_buffer` is always called with `ola_hop_size` - Thus, the rendered frames are always cleared immediately after processing, and `num_complete_frames` is 0 in the delay calculation. - The factors contributing to delay are: - the pending samples in the input buffer according to the search block position, and - the pending rendered samples in the output buffer (always empty in practice). The frame_delay code looked like that of the rubberband filter, which might not work for scaletempo2. Sometimes a different amount of input audio was consumed by scaletempo2 than expected. It may have been caused by speed changes being a more dynamic process in scaletempo2. This can be seen by where `playback_rate` is used in `run_one_wsola_iteration`: `playback_rate` is only referenced after the iteration, when updating the time and removing old data from buffers. In scaletempo2, the playback speed is applied by changing the amount the search block is moved. That apparently averages out correctly at constant playback speed, but when the speed changes, the error in this assumption probably spikes. This error accumulated across all speed changes because of the persistent `frame_delay` value. With the removal of the persistent `frame_delay`, there should be no way for the audio to drift off. By deriving the delay from filter buffer positions, and the buffers are filled only as much as needed, the delay always stays within buffer bounds. |
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| .. | ||
| decode | ||
| filter | ||
| out | ||
| aframe.c | ||
| aframe.h | ||
| chmap_avchannel.c | ||
| chmap_avchannel.h | ||
| chmap_sel.c | ||
| chmap_sel.h | ||
| chmap.c | ||
| chmap.h | ||
| fmt-conversion.c | ||
| fmt-conversion.h | ||
| format.c | ||
| format.h | ||