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[79.124.17.100]) by mx.google.com with ESMTP id cw15si34090042ejc.604.2021.07.23.02.34.33; Fri, 23 Jul 2021 02:34:33 -0700 (PDT) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 595E668ACE2; Fri, 23 Jul 2021 12:34:19 +0300 (EEST) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mout-p-102.mailbox.org (mout-p-102.mailbox.org [80.241.56.152]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 49C2268A922 for ; Fri, 23 Jul 2021 12:34:10 +0300 (EEST) Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:105:465:1:2:0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-102.mailbox.org (Postfix) with ESMTPS id 4GWPKG2s3mzQjgX for ; Fri, 23 Jul 2021 11:34:10 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by spamfilter02.heinlein-hosting.de (spamfilter02.heinlein-hosting.de [80.241.56.116]) (amavisd-new, port 10030) with ESMTP id r66pKGUXDmVA for ; Fri, 23 Jul 2021 11:34:07 +0200 (CEST) From: Gyan Doshi To: ffmpeg-devel@ffmpeg.org Date: Fri, 23 Jul 2021 15:03:41 +0530 Message-Id: <20210723093341.2000-2-ffmpeg@gyani.pro> In-Reply-To: <20210723093341.2000-1-ffmpeg@gyani.pro> References: <20210723093341.2000-1-ffmpeg@gyani.pro> MIME-Version: 1.0 X-Rspamd-Queue-Id: 948EA1849 X-Rspamd-UID: afcb82 Subject: [FFmpeg-devel] [PATCH 2/2] avcodec/noise: allow various cadence for dropping packets 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 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: qgdEH26wpnYB Packets can now be dropped at fixed intervals or with varying degrees of irregularity --- doc/bitstream_filters.texi | 22 +++++++++++++ libavcodec/noise_bsf.c | 65 ++++++++++++++++++++++++++++++-------- libavcodec/version.h | 2 +- 3 files changed, 74 insertions(+), 15 deletions(-) diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi index 2b84bda1fc..4ab6cc15ab 100644 --- a/doc/bitstream_filters.texi +++ b/doc/bitstream_filters.texi @@ -539,6 +539,22 @@ with @var{1} meaning every byte is modified. Default is @var{0}. @item dropamount Accepts a positive integer. Lower the value, more frequently packets will be dropped, with @var{1} meaning every packet is dropped. Default is @var{0}. +@item drop_pattern +Regulate how packets are dropped, starting with packet index of @var{drop_offset}. +Possible values are +@table @option +@item 0 (@emph{default}) +Drop at fixed intervals of @var{dropamount}, e.g. with dropamount @var{5} and drop_offset @var{2}, +packets no. @code{2, 7, 12...} will be dropped. +@item 1 +Drop a random packet in each interval of size @var{dropamount}. +@item 2 +Drop a random packet in roughly inverse frequency to @var{dropamount}. Over a short range of packets, +the drop frequency is less stable than pattern value @var{1}. +@end table +@item drop_offset +Accepts a positive integer. Represents the index of the first packet at which drop evaluations +start. Default is @var{0}. @end table The following example applies the modification to every byte but does not drop @@ -547,6 +563,12 @@ any packets. ffmpeg -i INPUT -c copy -bsf noise=amount=1 output.mkv @end example +The following example drops one random packet every 5 packets starting with packet #2 and modifies +roughly every 3rd byte of remaining packets. +@example +ffmpeg -i INPUT -c copy -bsf noise=amount=3:dropamount=5:drop_pattern=1:drop_offset=2 output.mkv +@end example + @section null This bitstream filter passes the packets through unchanged. diff --git a/libavcodec/noise_bsf.c b/libavcodec/noise_bsf.c index c1b0203442..83118c12cf 100644 --- a/libavcodec/noise_bsf.c +++ b/libavcodec/noise_bsf.c @@ -30,7 +30,12 @@ typedef struct NoiseContext { const AVClass *class; int amount; int dropamount; + int drop_pattern; + int drop_offset; + unsigned int state; + unsigned int pkt_idx; + unsigned int drop_idx; } NoiseContext; static int noise_init(AVBSFContext *ctx) @@ -48,31 +53,61 @@ static int noise_init(AVBSFContext *ctx) static int noise(AVBSFContext *ctx, AVPacket *pkt) { NoiseContext *s = ctx->priv_data; - int i, ret; + int i, ret, interval_pos, drop; ret = ff_bsf_get_packet_ref(ctx, pkt); if (ret < 0) return ret; - if (s->dropamount && s->state % s->dropamount == 0) { - s->state++; - av_packet_unref(pkt); - return AVERROR(EAGAIN); + if (s->dropamount && s->pkt_idx >= s->drop_offset) { + + interval_pos = (s->pkt_idx - s->drop_offset) % s->dropamount; + + switch (s->drop_pattern) { + case 0: + drop = interval_pos == 0; + break; + case 1: + if (interval_pos == 0) + s->drop_idx = s->pkt_idx + s->state % s->dropamount; + drop = s->pkt_idx == s->drop_idx; + break; + case 2: + drop = s->state % s->dropamount == 0; + break; + } + + if (drop) { + av_log(ctx, AV_LOG_VERBOSE, "Stream #%d packet #%d with pts %"PRId64" dropped.\n", pkt->stream_index, s->pkt_idx, pkt->pts); + s->state++; + av_packet_unref(pkt); + ret = AVERROR(EAGAIN); + goto done; + } } - ret = av_packet_make_writable(pkt); - if (ret < 0) { - av_packet_unref(pkt); - return ret; + if (s->amount) { + ret = av_packet_make_writable(pkt); + if (ret < 0) { + av_packet_unref(pkt); + goto done; + } } - for (i = 0; i < pkt->size; i++) { - s->state += pkt->data[i] + 1; - if (s->amount && s->state % s->amount == 0) - pkt->data[i] = s->state; + if (s->amount || s->drop_pattern) { + + for (i = 0; i < pkt->size; i++) { + s->state += pkt->data[i] + 1; + if (s->amount && s->state % s->amount == 0) + pkt->data[i] = s->state; + } } - return 0; + ret = 0; + +done: + s->pkt_idx++; + return ret; } #define OFFSET(x) offsetof(NoiseContext, x) @@ -80,6 +115,8 @@ static int noise(AVBSFContext *ctx, AVPacket *pkt) static const AVOption options[] = { { "amount", NULL, OFFSET(amount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS }, { "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS }, + { "drop_pattern", NULL, OFFSET(drop_pattern), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, FLAGS }, + { "drop_offset", NULL, OFFSET(drop_offset), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS }, { NULL }, }; diff --git a/libavcodec/version.h b/libavcodec/version.h index c660f70669..91325ce4e7 100644 --- a/libavcodec/version.h +++ b/libavcodec/version.h @@ -29,7 +29,7 @@ #define LIBAVCODEC_VERSION_MAJOR 59 #define LIBAVCODEC_VERSION_MINOR 3 -#define LIBAVCODEC_VERSION_MICRO 101 +#define LIBAVCODEC_VERSION_MICRO 102 #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \ LIBAVCODEC_VERSION_MINOR, \