FFmpeg

Commit Graph

Author	SHA1	Message	Date
Claudio Freire	62dfe1d40d	avcodec/aacenc_is: replace pow(x, 0.75) by x/sqrtf(sqrtf(x)) This is quite an accurate approximation; testing shows ~ 2ulp error in the floating point result. Tested with FATE. Alternatively, if one wants "full accuracy", one can use powf, or sqrt instead of sqrtf. With powf, one gets 1 ulp error (theoretically should be 0, as 0.75 is exactly representable) on GNU libm, with sqrt, 0 ulp error. Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com> Abstracted into pos_pow34 utility function Signed-off-by: Claudio Freire <klaussfreire@gmail.com>	9 years ago
Rostislav Pehlivanov	ade31b9424	aacenc: switch to using the RNG from libavutil PSNR doesn't change as expected. The AAC spec doesn't really say anything about how exactly to generate noise. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	9 years ago
Claudio Freire	ca203e9985	AAC encoder: improve SF range utilization This patch does 4 things, all of which interact and thus it woudln't be possible to commit them separately without causing either quality regressions or assertion failures. Fate comparison targets don't all reflect improvements in quality, yet listening tests show substantially improved quality and stability. 1. Increase SF range utilization. The spec requires SF delta values to be constrained within the range -60..60. The previous code was applying that range to the whole SF array and not only the deltas of consecutive values, because doing so requires smarter code: zeroing or otherwise skipping a band may invalidate lots of SF choices. This patch implements that logic to allow the coders to utilize the full dynamic range of scalefactors, increasing quality quite considerably, and fixing delta-SF-related assertion failures, since now the limitation is enforced rather than asserted. 2. PNS tweaks The previous modification makes big improvements in twoloop's efficiency, and every time that happens PNS logic needs to be tweaked accordingly to avoid it from stepping all over twoloop's decisions. This patch includes modifications of the sort. 3. Account for lowpass cutoff during PSY analysis The closer PSY's allocation is to final allocation the better the quality is, and given these modifications, twoloop is now very efficient at avoiding holes. Thus, to compute accurate thresholds, PSY needs to account for the lowpass applied implicitly during twoloop (by zeroing high bands). This patch makes twoloop set the cutoff in psymodel's context the first time it runs, and makes PSY account for it during threshold computation, making PE and threshold computations closer to the final allocation and thus achieving better subjective quality. 4. Tweaks to RC lambda tracking loop in relation to PNS Without this tweak some corner cases cause quality regressions. Basically, lambda needs to react faster to overall bitrate efficiency changes since now PNS can be quite successful in enforcing maximum bitrates, when PSY allocates too many bits to the lower bands, suppressing the signals RC logic uses to lower lambda in those cases and causing aggressive PNS. This tweak makes PNS much less aggressive, though it can still use some further tweaks. Also update MIPS specializations and adjust fuzz Also in lavc/mips/aacpsy_mips.h: remove trailing whitespace	9 years ago
Ganesh Ajjanagadde	79abf2d0de	avcodec/aac_tablegen: get rid of hardcoded tables entirely Commit `96786a12f6` makes runtime initialization cheap. Tested with FATE, with/without --enable-hardcoded-tables. Reviewed-by: Rostislav Pehlivanov <atomnuker@gmail.com> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>	9 years ago
Rostislav Pehlivanov	e9299df7a6	aacenc: partially revert previous commits to set options via a profile It didn't work out because of the exceptions that needed to be made for the "-1" cases and was overall more confusing that just manually checking and setting options for each profile.	9 years ago
Rostislav Pehlivanov	e2749ef60a	aacenc_utils: fit find_form_factor() below 80 chars per line	9 years ago
Rostislav Pehlivanov	0f4334df45	aacenc: add support for changing options based on a profile This commit adds the ability for a profile to set the default options, as well as for the user to override such options by simply stating them in the command line while still keeping the same profile, as long as those options are still permitted by the profile. Example: setting the profile to aac_low (the default) will turn PNS and IS on. They can be disabled by -aac_pns 0 and -aac_is 0, respectively. Turning on -aac_pred 1 will cause the profile to be elevated to aac_main, as long as no options forbidding aac_main have been entered (like AAC-LTP, which will be pushed soon). A useful feature is that by setting the profile to mpeg2_aac_low, all MPEG4 features will be disabled and if the user tries to enable them then the program will exit with an error. This profile is signalled with the same bitstream as aac_low (MPEG4) but some devices and decoders will fail if any MPEG4 features have been enabled.	9 years ago
Rostislav Pehlivanov	5f760da6b6	aacenc_utils: add 'inline' flag to find_form_factor, silence warning Seems it was forgotten.	9 years ago
Claudio Freire	01ecb7172b	AAC encoder: Extensive improvements This finalizes merging of the work in the patches in ticket #2686. Improvements to twoloop and RC logic are extensive. The non-exhaustive list of twoloop improvments includes: - Tweaks to distortion limits on the RD optimization phase of twoloop - Deeper search in twoloop - PNS information marking to let twoloop decide when to use it (turned out having the decision made separately wasn't working) - Tonal band detection and priorization - Better band energy conservation rules - Strict hole avoidance For rate control: - Use psymodel's bit allocation to allow proper use of the bit reservoir. Don't work against the bit reservoir by moving lambda in the opposite direction when psymodel decides to allocate more/less bits to a frame. - Retry the encode if the effective rate lies outside a reasonable margin of psymodel's allocation or the selected ABR. - Log average lambda at the end. Useful info for everyone, but especially for tuning of the various encoder constants that relate to lambda feedback. Psy: - Do not apply lowpass with a FIR filter, instead just let the coder zero bands above the cutoff. The FIR filter induces group delay, and while zeroing bands causes ripple, it's lost in the quantization noise. - Experimental VBR bit allocation code - Tweak automatic lowpass filter threshold to maximize audio bandwidth at all bitrates while still providing acceptable, stable quality. I/S: - Phase decision fixes. Unrelated to #2686, but the bugs only surfaced when the merge was finalized. Measure I/S band energy accounting for phase, and prevent I/S and M/S from being applied both. PNS: - Avoid marking short bands with PNS when they're part of a window group in which there's a large variation of energy from one window to the next. PNS can't preserve those and the effect is extremely noticeable. M/S: - Implement BMLD protection similar to the specified in ISO-IEC/13818:7-2003, Appendix C Section 6.1. Since M/S decision doesn't conform to section 6.1, a different method had to be implemented, but should provide equivalent protection. - Move the decision logic closer to the method specified in ISO-IEC/13818:7-2003, Appendix C Section 6.1. Specifically, make sure M/S needs less bits than dual stereo. - Don't apply M/S in bands that are using I/S Now, this of course needed adjustments in the compare targets and fuzz factors of the AAC encoder's fate tests, but if wondering why the targets go up (more distortion), consider the previous coder was using too many bits on LF content (far more than required by psy), and thus those signals will now be more distorted, not less. The extra distortion isn't audible though, I carried extensive ABX testing to make sure. A very similar patch was also extensively tested by Kamendo2 in the context of #2686.	9 years ago
Claudio Freire	b01f3ddad3	AAC encoder: simplify and speed up find_min_book Trivial change to simplify the small but hot find_min_book function. The new form is easier to understand and faster.	9 years ago
Rostislav Pehlivanov	92aa3e7fb2	aacenc: copy PRNG from the decoder Needed for the following PNS commits. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>	9 years ago
Rostislav Pehlivanov	ef8e5a61c8	aacenc: Move small misc. functions to a separate file As well as tables littered everywhere, functions were spread out all across the encoder's files. This moves them to a single place where they can be used by either the encoder's main files or additional encoder files. Additionally, it changes the type of some to 'inline' to enable us to simply put them in a header file and possibly gain some speed due to compiler optimizations. Signed-off-by: Claudio Freire <klaussfreire@gmail.com>	10 years ago

12 Commits (fea9243d53e0e281450e39ec0e1b4b3c122a8a29)