From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 1F0B246DEC for ; Wed, 12 Jul 2023 23:38:25 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id D60C068C64F; Thu, 13 Jul 2023 02:37:24 +0300 (EEST) Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 6634368C651 for ; Thu, 13 Jul 2023 02:37:20 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id BBD971BF203 for ; Wed, 12 Jul 2023 23:37:19 +0000 (UTC) From: Michael Niedermayer To: FFmpeg development discussions and patches Date: Thu, 13 Jul 2023 01:37:05 +0200 Message-Id: <20230712233706.449054-13-michael@niedermayer.cc> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230712233706.449054-1-michael@niedermayer.cc> References: <20230712233706.449054-1-michael@niedermayer.cc> MIME-Version: 1.0 X-GND-Sasl: michael@niedermayer.cc Subject: [FFmpeg-devel] [PATCH 13/14] avradio/sdrdemux: deemphasis filter fixes X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Signed-off-by: Michael Niedermayer --- libavradio/sdrdemux.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/libavradio/sdrdemux.c b/libavradio/sdrdemux.c index 54d7622809..b69b13d075 100644 --- a/libavradio/sdrdemux.c +++ b/libavradio/sdrdemux.c @@ -67,7 +67,7 @@ #define AM_MAX4 0.02 //Least squares fit at 1khz points of frequency response shown by Frank McClatchie, FM SYSTEMS, INC. 800-235-6960 -static double emphasis75us(int f) +static double emphasis75us(double f) { return ((((((((- 4.79546E-9 * f + 5.32101E-7) * f - 0.0000254577) * f + 0.000687225) * f - 0.0114925) * f + 0.122781 ) * f - 0.827885 ) * f + 3.25025 ) * f - 4.6049) * f + 2.06937; @@ -76,15 +76,16 @@ static double emphasis75us(int f) /** * Apply emphasis filter in frequency domain */ -static void apply_deemphasis(SDRContext *sdr, AVComplexFloat *data, int len, int sample_rate, int dir) +static void apply_deemphasis(SDRContext *sdr, AVComplexFloat *data, int len, int block_size, int sample_rate, int dir) { + double factor = sample_rate / (2000.0*block_size); if (sdr->emphasis_mode == EMPHASIS_NONE) return; - len = FFMIN(len, len * 19000 / sample_rate); + len = FFMIN(len, len * 2 * 19000 / sample_rate); for (int i = 1; i < len; i++) { - double index = 1.0 + i / 1000; + double index = 1.0 + i * factor; double scale; if (sdr->emphasis_mode == EMPHASIS_50us) @@ -1051,8 +1052,8 @@ static int demodulate_fm(SDRContext *sdr, Station *station, AVStream *st, AVPack if (st) { memcpy(sdr->fm_block + i, sdr->fm_block + 2*carrier19_i, sizeof(AVComplexFloat)*len17_i); memcpy(sdr->fm_block + i + 2*sdr->fm_block_size_p2 - len17_i, sdr->fm_block + 2*carrier19_i - len17_i, sizeof(AVComplexFloat)*len17_i); - apply_deemphasis(sdr, sdr->fm_block + i, sdr->fm_block_size_p2, sample_rate_p2, + 1); - apply_deemphasis(sdr, sdr->fm_block + i + 2*sdr->fm_block_size_p2, sdr->fm_block_size_p2, sample_rate_p2, - 1); + apply_deemphasis(sdr, sdr->fm_block + i, sdr->fm_block_size_p2, sdr->fm_block_size_p2, sample_rate_p2, + 1); + apply_deemphasis(sdr, sdr->fm_block + i + 2*sdr->fm_block_size_p2, sdr->fm_block_size_p2, sdr->fm_block_size_p2, sample_rate_p2, - 1); sdr->fm_ifft_p2(sdr->fm_ifft_p2_ctx, sdr->fm_iside , sdr->fm_block + i, sizeof(AVComplexFloat)); synchronous_am_demodulationN(sdr->fm_iside, sdr->fm_icarrier, sdr->fm_window_p2, 2*sdr->fm_block_size_p2, 2); } @@ -1061,7 +1062,7 @@ static int demodulate_fm(SDRContext *sdr, Station *station, AVStream *st, AVPack return 0; memset(sdr->fm_block + len17_i, 0, (2*sdr->fm_block_size_p2 - len17_i) * sizeof(AVComplexFloat)); - apply_deemphasis(sdr, sdr->fm_block, 2*sdr->fm_block_size_p2, sample_rate_p2, + 1); + apply_deemphasis(sdr, sdr->fm_block, sdr->fm_block_size_p2, sdr->fm_block_size_p2, sample_rate_p2, + 1); sdr->fm_ifft_p2(sdr->fm_ifft_p2_ctx, sdr->fm_iblock , sdr->fm_block, sizeof(AVComplexFloat)); memset(sdr->fm_iblock + 2*sdr->fm_block_size_p2, 0 ,(2*sdr->fm_block_size -2*sdr->fm_block_size_p2) * sizeof(AVComplexFloat)); -- 2.31.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".