Chiebot-Mirror/FFmpeg - FFmpeg - Gitea: Git with a cup of tea

Author	SHA1	Message	Date
Rostislav Pehlivanov	8848c8440e	aacenc_pred: disable PNS SFBs and disable right predictors with IS Since PNS generates coefficients it doesn't make sense to send the predicted ones as well. Also the specifications explicitly state to disable right channel IS predictors. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	9 years ago
Rostislav Pehlivanov	4565611b04	aacenc_is: add a flag to use pure coefficients instead This commit adds a flag to use the pure coefficients instead of the processed ones (sce->coeffs). This is needed because IS will apply the changes to the coefficients immediately before the adjust_common_prediction function and it doesn't make sense to measure stereo channel coefficient difference when one of the channels coefficients are all zero. Therefore add a flag to use pure coefficients in that case. TNS is the only thing touching the coefficients before IS so common window prediction will not take that into account but the effect of the TNS filter per coefficient can be small (a few percent) so to some approximation it's fine to just ignore that. Also fixed a small error which doesn't alter the results that much. pow(sqrt(number), 3.0/4.0) == pow(number, 3.0/8.0) != pow(number, 3.0/4.0). Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	9 years ago
Rostislav Pehlivanov	44ddee945a	aacenc_pred: rework the way prediction is done This commit completely alters the algorithm of prediction. The original commit which introduced prediction was completely incorrect to even remotely care about what the actual coefficients contain or whether any options were enabled. Not my actual fault. This commit treats prediction the way the decoder does and expects to do: like lossy encryption. Everything related to prediction now happens at the very end but just before quantization and encoding of coefficients. On the decoder side, prediction happens before anything has had a chance to even access the coefficients. Also the original implementation had problems because it actually touched the band_type of special bands which already had their scalefactor indices marked and it's a wonder the asserion wasn't triggered when transmitting those. Overall, this now drastically increases audio quality and you should think about enabling it if you don't plan on playing anything encoded on really old low power ultra-embedded devices since they might not support decoding of prediction or AAC-Main. Though the specifications were written ages ago and as times change so do the FLOPS. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	9 years ago
Timothy Gu	21dd5279c3	aacenc: Add missing ff_ prefixes Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com> Reviewed-by: Ganesh Ajjanagadde <gajjanag@mit.edu>	10 years ago
Rostislav Pehlivanov	76b81b10d9	aacenc: implement the complete AAC-Main profile This commit finalizes AAC-Main profile encoding support by implementing all mandatory and optional tools available in the specifications and current decoders. The AAC-Main profile reqires that prediction support be present (although decoders don't require it to be enabled) for an encoder to be deemed capable of AAC-Main encoding, as well as TNS, PNS and IS, all of which were implemented with previous commits or earlier of this year. Users are encouraged to test the new functionality using either -profile:a aac_main or -aac_pred 1, the former of which will enable the prediction option by default and the latter will change the profile to AAC-Main. No other options shall be changed by enabling either, it's currently up to the users to decide what's best. The current implementation works best using M/S and/or IS, so users are also welcome to enable both options and any other options (TNS, PNS) for maximum quality. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	10 years ago