Hi. This patch introduces initial implementation of subband ADPCM encoding for DCA codec.
Some results: sample: https://yadi.sk/d/B_3sVskM3HZiWK - original https://yadi.sk/d/7CK47Nt63HZiWf - without adpcm https://yadi.sk/d/25q1JDV93HZiWq - with adpcm chirp tone: https://yadi.sk/i/tZKHoJ1d3HZk4c Right now this feature is disabled by default. But it is ready to try using -dca_adpcm 1 option. There are some issues, should be solved before enabling this feature by default: 1. Speed up: I am trying to find best filter in each subband. But with real signal, usually only few subbands has significant prediction gain. The idea is try to analyze FFT spectrum (which is already calculated), to check is particular subband looks like tonal or noise. If subband is noise like - do not try to find best LPC predictor. 2. Modify psychoacoustic to use prediction gain for bit allocation. Right now ADPCM encoded block can get some extra bits. 3. Tuning the prediction gain threshold. Thank you. -- Daniil Cherednik
0001-avcodec-dcaenc-Initial-implementation-of-ADPCM-encod.patch
Description: Binary data
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
