Linear Predictive Coding
| EditDate | 2025-2-13 |
|---|
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This is the heart of both fLaC compression and predicting the next sound, I think
Going to decode here and see how easily it can be introduced into my playAlong code.Web References https://en.wikipedia.org/wiki/Linear prediction
Linear Predictive Coding
| Line Number | Code Package | LOC purpose | Operation Description |
|---|---|---|---|
| 2987 | SDC | read_residual_partitioned_rice | sample += u; Key parameters
|
| 2883 | SDC | read_subframe_lpc | break |
| 2889 | SDC | Do Full Decode | |
| 2892 | SDC | Get Warm-up values | 8 previously stored warm-up values based on order=8 |
| 2894 | SDC | call FLAC lpc max bps | |
| 960 | LPC | FLAC__lpc_max_residual_bps | Variables
Address 0 - 3 4 - 7 8 - B C - F 0000555555859EF0 08000000 0F000000 0D000000 E51D0000 0000555555859F00 282E0000 E0E2FFFF F4CFFFFF 170C0000 0000555555859F10 17210000 72010000 6EF2FFFF
|
| 948 | LPC | FLAC__lpc_max_prediction_before_shift_bps | |
| 2895 | SDC | read_subframe_lpc_ | Checks less than 32 bits |
| 2898 | SDC | read_subframe_lpc_ | FLAC__lpc_restore_signal_wide |
Pertinent Code
960 LPC FLAC__int32 predictor_sum_bps = FLAC__lpc_max_prediction_before_shift_bps(subframe_bps, qlp_coeff, order) - lp_quantization;
Notes for code analysis
4 bytes / int 32 Bits.
little endian memory dump of in storage buffer
19 7F D1 4F 19 7F D1 4F 19 7F D1 4F FD 44 01 37 56 26 0A 25 B2 EE F6 7F 9D 10 5D 79 62 33 5B 9F B4 0E 65 24 15 7A 35 13 370144FD4FD17F19 at 2380 in test.flac.
File
3701 44FD 4FD1 4FD1 7F19 7FF6 EEB2 250A 2656 does not line up with contiguous memory location. Only 64 bit word valid in memory (if reversed) loc 2380 in file
word