ac3enc_fixed: convert to 32-bit sample format The AC3 encoder used to be a separate library called "Aften", which got merged into libavcodec (literally, SVN commits and all). The merge preserved as much features from the library as possible. The code had two versions - a fixed point version and a floating point version. FFmpeg had floating point DSP code used by other codecs, the AC3 decoder including, so the floating-point DSP was simply replaced with FFmpeg's own functions. However, FFmpeg had no fixed-point audio code at that point. So the encoder brought along its own fixed-point DSP functions, including a fixed-point MDCT. The fixed-point MDCT itself is trivially just a float MDCT with a different type and each multiply being a fixed-point multiply. So over time, it got refactored, and the FFT used for all other codecs was templated. Due to design decisions at the time, the fixed-point version of the encoder operates at 16-bits of precision. Although convenient, this, even at the time, was inadequate and inefficient. The encoder is noisy, does not produce output comparable to the float encoder, and even rings at higher frequencies due to the badly approximated winow function. Enter MIPS (owned by Imagination Technologies at the time). They wanted quick fixed-point decoding on their FPUless cores. So they contributed patches to template the AC3 decoder so it had both a fixed-point and a floating-point version. They also did the same for the AAC decoder. They however, used 32-bit samples. Not 16-bits. And we did not have 32-bit fixed-point DSP functions, including an MDCT. But instead of templating our MDCT to output 3 versions (float, 32-bit fixed and 16-bit fixed), they simply copy-pasted their own MDCT into ours, and completely ifdeffed our own MDCT code out if a 32-bit fixed point MDCT was selected. This is also the status quo nowadays - 2 separate MDCTs, one which produces floating point and 16-bit fixed point versions, and one sort-of integrated which produces 32-bit MDCT. MIPS weren't all that interested in encoding, so they left the encoder as-is, and they didn't care much about the ifdeffery, mess or quality - it's not their problem. So the MDCT/FFT code has always been a thorn in anyone looking to clean up code's eye. Backstory over. Internally AC3 operates on 25-bit fixed-point coefficients. So for the floating point version, the encoder simply runs the float MDCT, and converts the resulting coefficients to 25-bit fixed-point, as AC3 is inherently a fixed-point codec. For the fixed-point version, the input is 16-bit samples, so to maximize precision the frame samples are analyzed and the highest set bit is detected via ac3_max_msb_abs_int16(), and the coefficients are then scaled up via ac3_lshift_int16(), so the input for the FFT is always at least 14 bits, computed in normalize_samples(). After FFT, the coefficients are scaled up to 25 bits. This patch simply changes the encoder to accept 32-bit samples, reusing the already well-optimized 32-bit MDCT code, allowing us to clean up and drop a large part of a very messy code of ours, as well as prepare for the future lavu/tx conversion. The coefficients are simply scaled down to 25 bits during windowing, skipping 2 separate scalings, as the hacks to extend precision are simply no longer necessary. There's no point in running the MDCT always at 32 bits when you're going to drop 6 bits off anyway, the headroom is plenty, and the MDCT rounds properly. This also makes the encoder even slightly more accurate over the float version, as there's no coefficient conversion step necessary. SIZE SAVINGS: ARM32: HARDCODED TABLES: BASE - 10709590 DROP DSP - 10702872 - diff: -6.56KiB DROP MDCT - 10667932 - diff: -34.12KiB - both: -40.68KiB DROP FFT - 10336652 - diff: -323.52KiB - all: -364.20KiB SOFTCODED TABLES: BASE - 9685096 DROP DSP - 9678378 - diff: -6.56KiB DROP MDCT - 9643466 - diff: -34.09KiB - both: -40.65KiB DROP FFT - 9573918 - diff: -67.92KiB - all: -108.57KiB ARM64: HARDCODED TABLES: BASE - 14641112 DROP DSP - 14633806 - diff: -7.13KiB DROP MDCT - 14604812 - diff: -28.31KiB - both: -35.45KiB DROP FFT - 14286826 - diff: -310.53KiB - all: -345.98KiB SOFTCODED TABLES: BASE - 13636238 DROP DSP - 13628932 - diff: -7.13KiB DROP MDCT - 13599866 - diff: -28.38KiB - both: -35.52KiB DROP FFT - 13542080 - diff: -56.43KiB - all: -91.95KiB x86: HARDCODED TABLES: BASE - 12367336 DROP DSP - 12354698 - diff: -12.34KiB DROP MDCT - 12331024 - diff: -23.12KiB - both: -35.46KiB DROP FFT - 12029788 - diff: -294.18KiB - all: -329.64KiB SOFTCODED TABLES: BASE - 11358094 DROP DSP - 11345456 - diff: -12.34KiB DROP MDCT - 11321742 - diff: -23.16KiB - both: -35.50KiB DROP FFT - 11276946 - diff: -43.75KiB - all: -79.25KiB PERFORMANCE (10min random s32le): ARM32 - before - 39.9x - 0m15.046s ARM32 - after - 28.2x - 0m21.525s Speed: -30% ARM64 - before - 36.1x - 0m16.637s ARM64 - after - 36.0x - 0m16.727s Speed: -0.5% x86 - before - 184x - 0m3.277s x86 - after - 190x - 0m3.187s Speed: +3%

- [D] tests/fate/ffmpeg.mak

fate: disable automatic conversions on many tests. Explicitly insert the scale or aresample filter where it would have been inserted by the negotiation. Re-enable conversions if it cannot be done easily. If a conversion is needed in a test, we want to know about it. If the negotiation changes and makes new conversion necessary, we want to know about it even more.

- [D] tests/fate/ffmpeg.mak

fate/ffmpeg: add test for time limited sub2video instance Utilizes a subpicture sample with one decodable subpicture for the test. Based on a failing test case in reported by Michael in https://ffmpeg.org/pipermail/ffmpeg-devel/2019-February/240398.html which at the time had no test case for it. Additionally, this is the first test case for the presentation graphics format.

- [D] tests/fate/ffmpeg.mak

fate/ffmpeg: add a second, simple sub2video test

- [D] tests/fate/ffmpeg.mak

fate: Fix dependencies to sample files to use local paths These dependencies are evaluted by make and must be expressed with the paths as in the local filesystem. Signed-off-by: Martin Storsjö <martin@martin.st>

- [D] tests/fate/ffmpeg.mak

fate: add test for stream_loop Checks that seek to start indeed seeks to start.

- [D] tests/fate/ffmpeg.mak

tests: don't include TARGET_PATH in the sample path needlessly The transcode() helper function will already prepend the TARGET_PATH to the sample path, if its a relative path. This avoids an issue on Windows, where the relative path check could fail.

- [D] tests/fate/ffmpeg.mak

tests/fate/ffmpeg: Check for apng codec for fate-copy-apng. The file has to be created first, fixes fate without zlib.

- [D] tests/fate/ffmpeg.mak

Merge commit 'f8df5e2f31a5ba7b30a0e1caaaf5a03c753b3f9b' * commit 'f8df5e2f31a5ba7b30a0e1caaaf5a03c753b3f9b': tests: Add a convenience function for video-only lavf tests Merged-by: James Almer <jamrial@gmail.com>

- [D] tests/fate/ffmpeg.mak

fate: change fate-ffmpeg-attached_pics to encode to pcm_s16le Previously alac encoder was used, from a first glance I thought it is bitexact, but it turns out it is using floating point arithmetic as well, so probably it is not. Fixes fate failures on mingw32/64. Signed-off-by: Marton Balint <cus@passwd.hu>

- [D] tests/fate/ffmpeg.mak

fate: fix ffmpeg-attached_pics test dependencies Signed-off-by: Marton Balint <cus@passwd.hu>

- [D] tests/fate/ffmpeg.mak

fate: add fate test for ticket #6375 Signed-off-by: Marton Balint <cus@passwd.hu>

- [D] tests/fate/ffmpeg.mak

fate: add fate test for ticket #6603 Signed-off-by: Marton Balint <cus@passwd.hu>

- [D] tests/fate/ffmpeg.mak

Merge commit '4141a5a240fba44b4b4a1c488c279d7dd8a11ec7' * commit '4141a5a240fba44b4b4a1c488c279d7dd8a11ec7': Use modern avconv syntax for codec selection in documentation and tests Merged-by: James Almer <jamrial@gmail.com>

- [D] tests/fate/ffmpeg.mak

ffmpeg options: Enable trailing ? for map_channel The -map option allows for a trailing ? so that an error is not thrown if the input stream does not exist. This capability is extended to the map_channel option. This allows a ffmpeg command not to break if an input channel does not exist, which can be of use (for instance, scripts processing audio channels with sources having unset number of audio channels). Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

- [D] tests/fate/ffmpeg.mak

fate: Add fate-copy-trac3074 Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

- [D] tests/fate/ffmpeg.mak

fate: add test for -time_base option Signed-off-by: Michael Bradshaw <mjbshaw@google.com> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

- [D] tests/fate/ffmpeg.mak

Merge commit '043b0b9fb1481053b712d06d2c5b772f1845b72b' * commit '043b0b9fb1481053b712d06d2c5b772f1845b72b': Replace leftover uses of -aframes|-dframes|-vframes with -frames:a|d|v The merge also includes all our own occurences. Merged-by: Clément Bœsch <u@pkh.me>

- [D] tests/fate/ffmpeg.mak

fate/colorkey: disable audio stream. The test is not supposed to cover audio. Also, using -vframes along with an audio stream depends on the exact order the frames are processed by filters, it is too much constraint to guarantee.

- [D] tests/fate/ffmpeg.mak

fate: add bsf tests for ticket 5927 Tested-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: James Almer <jamrial@gmail.com>

- [D] tests/fate/ffmpeg.mak