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| author | Justin Ruggles <justin.ruggles@gmail.com> | 2011-12-07 11:56:57 -0500 |
|---|---|---|
| committer | Justin Ruggles <justin.ruggles@gmail.com> | 2012-01-03 13:15:24 -0500 |
| commit | e49d21306a49c09bdf66435b73ea01384a5645ae (patch) | |
| tree | cfa8c1667085569c238f3be12402a8566eaaf009 /libavcodec/alac.c | |
| parent | bb63475aec53e001ad84a24ed6e2a23ad1697fc8 (diff) | |
| download | ffmpeg-e49d21306a49c09bdf66435b73ea01384a5645ae.tar.gz | |
alacdec: implement the 2-pass prediction type.
The reference encoder does not generate any streams using this, but the
reference decoder can handle it, so we should as well.
Diffstat (limited to 'libavcodec/alac.c')
| -rw-r--r-- | libavcodec/alac.c | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/libavcodec/alac.c b/libavcodec/alac.c index eb6c1cfc16..278cc99969 100644 --- a/libavcodec/alac.c +++ b/libavcodec/alac.c @@ -452,24 +452,29 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data, ricemodifier[ch] * alac->setinfo_rice_historymult / 4, (1 << alac->setinfo_rice_kmodifier) - 1); - if (prediction_type[ch] == 0) { - /* adaptive fir */ - predictor_decompress_fir_adapt(alac->predicterror_buffer[ch], - alac->outputsamples_buffer[ch], - outputsamples, - readsamplesize, - predictor_coef_table[ch], - predictor_coef_num[ch], - prediction_quantitization[ch]); - } else { - av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[ch]); - /* I think the only other prediction type (or perhaps this is - * just a boolean?) runs adaptive fir twice.. like: - * predictor_decompress_fir_adapt(predictor_error, tempout, ...) - * predictor_decompress_fir_adapt(predictor_error, outputsamples ...) - * little strange.. + /* adaptive FIR filter */ + if (prediction_type[ch] == 15) { + /* Prediction type 15 runs the adaptive FIR twice. + * The first pass uses the special-case coef_num = 31, while + * the second pass uses the coefs from the bitstream. + * + * However, this prediction type is not currently used by the + * reference encoder. */ + predictor_decompress_fir_adapt(alac->predicterror_buffer[ch], + alac->predicterror_buffer[ch], + outputsamples, readsamplesize, + NULL, 31, 0); + } else if (prediction_type[ch] > 0) { + av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n", + prediction_type[ch]); } + predictor_decompress_fir_adapt(alac->predicterror_buffer[ch], + alac->outputsamples_buffer[ch], + outputsamples, readsamplesize, + predictor_coef_table[ch], + predictor_coef_num[ch], + prediction_quantitization[ch]); } } else { /* not compressed, easy case */ |