[FFmpeg-devel] [PATCH v2] avcodec/noise_bsf: add expr support
Gyan Doshi
ffmpeg at gyani.pro
Wed Jul 28 07:26:35 EEST 2021
---
doc/bitstream_filters.texi | 64 ++++++++++++---
libavcodec/noise_bsf.c | 161 +++++++++++++++++++++++++++++++++----
tests/fate/matroska.mak | 2 +-
3 files changed, 199 insertions(+), 28 deletions(-)
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index d10842ae47..46e4869f80 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -534,20 +534,62 @@ container. Can be used for fuzzing or testing error resilience/concealment.
Parameters:
@table @option
@item amount
-A numeral string, whose value is related to how often output bytes will
-be modified. Therefore, values below or equal to 0 are forbidden, and
-the lower the more frequent bytes will be modified, with 1 meaning
-every byte is modified.
- at item dropamount
-A numeral string, whose value is related to how often packets will be dropped.
-Therefore, values below or equal to 0 are forbidden, and the lower the more
-frequent packets will be dropped, with 1 meaning every packet is dropped.
+Accepts an expression whose evaluation per-packet determines how often bytes in that
+packet will be modified. A value below 0 will result in a variable frequency.
+Default is 0 which results in no modification. However, if neither amount or drop is specified,
+amount will be set to @var{-1}. See below for accepted variables.
+ at item drop, dropamount
+Accepts an expression evaluated per-packet whose value determines whether that packet is dropped.
+Evaluation to a positive value results in the packet being dropped. Evaluation to a negative
+value results in a variable chance of it being dropped, roughly inverse in proportion to the magnitude
+of the value. Default is 0 which results in no drops. See below for accepted variables.
@end table
-The following example applies the modification to every byte but does not drop
-any packets.
+Both @code{amount} and @code{drop} accept expressions containing the following variables:
+
+ at table @samp
+ at item n
+The index of the packet, starting from zero.
+ at item tb
+The timebase for packet timestamps.
+ at item pts
+Packet presentation timestamp.
+ at item dts
+Packet decoding timestamp.
+ at item nopts
+Constant representing AV_NOPTS_VALUE.
+ at item startpts
+First non-AV_NOPTS_VALUE PTS seen in the stream.
+ at item startdts
+First non-AV_NOPTS_VALUE DTS seen in the stream.
+ at item duration
+ at itemx d
+Packet duration, in timebase units.
+ at item pos
+Packet position in input; may be -1 when unknown or not set.
+ at item size
+Packet size, in bytes.
+ at item key
+Whether packet is marked as a keyframe.
+ at item state
+A pseudo random integer, primarily derived from the content of packet payload.
+ at end table
+
+ at subsection Examples
+Apply modification to every byte but don't drop any packets.
+ at example
+ffmpeg -i INPUT -c copy -bsf noise=1 output.mkv
+ at end example
+
+Drop every video packet not marked as a keyframe after timestamp 30s but do not
+modify any of the remaining packets.
+ at example
+ffmpeg -i INPUT -c copy -bsf:v noise=drop='gt(t\,30)*not(key)' output.mkv
+ at end example
+
+Drop one second of audio every 10 seconds and add some random noise to the rest.
@example
-ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
+ffmpeg -i INPUT -c copy -bsf:a noise=amount=-1:drop='between(mod(t\,10)\,9\,10)' output.mkv
@end example
@section null
diff --git a/libavcodec/noise_bsf.c b/libavcodec/noise_bsf.c
index 6ebd369633..9d7ef93001 100644
--- a/libavcodec/noise_bsf.c
+++ b/libavcodec/noise_bsf.c
@@ -23,55 +23,182 @@
#include "bsf.h"
#include "bsf_internal.h"
+#include "libavutil/avstring.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
+#include "libavutil/eval.h"
+
+static const char *const var_names[] = {
+ "n", /// packet index, starting from zero
+ "tb", /// timebase
+ "pts", /// packet presentation timestamp
+ "dts", /// packet decoding timestamp
+ "nopts", /// AV_NOPTS_VALUE
+ "startpts", /// first seen non-AV_NOPTS_VALUE packet timestamp
+ "startdts", /// first seen non-AV_NOPTS_VALUE packet timestamp
+ "duration", "d", /// packet duration
+ "pos", /// original position of packet in its source
+ "size", /// packet size
+ "key" , /// packet keyframe flag
+ "state", /// random-ish state
+ NULL
+};
+
+enum var_name {
+ VAR_N,
+ VAR_TB,
+ VAR_PTS,
+ VAR_DTS,
+ VAR_NOPTS,
+ VAR_STARTPTS,
+ VAR_STARTDTS,
+ VAR_DURATION, VAR_D,
+ VAR_POS,
+ VAR_SIZE,
+ VAR_KEY,
+ VAR_STATE,
+ VAR_VARS_NB
+};
typedef struct NoiseContext {
const AVClass *class;
- int amount;
- int dropamount;
+
+ char *amount_str;
+ char *drop_str;
+
+ AVExpr *amount_pexpr;
+ AVExpr *drop_pexpr;
+
+ double var_values[VAR_VARS_NB];
+
unsigned int state;
+ unsigned int pkt_idx;
} NoiseContext;
-static int noise(AVBSFContext *ctx, AVPacket *pkt)
+static int noise_init(AVBSFContext *ctx)
{
NoiseContext *s = ctx->priv_data;
- int amount = s->amount > 0 ? s->amount : (s->state % 10001 + 1);
- int i, ret;
+ int ret;
- if (amount <= 0)
- return AVERROR(EINVAL);
+ if (!s->amount_str) {
+ s->amount_str = !s->drop_str ? av_strdup("-1") : av_strdup("0");
+ if (!s->amount_str)
+ return AVERROR(ENOMEM);
+ }
+
+ ret = av_expr_parse(&s->amount_pexpr, s->amount_str,
+ var_names, NULL, NULL, NULL, NULL, 0, ctx);
+ if (ret < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for amount: %s\n", s->amount_str);
+ return ret;
+ }
+
+ if (s->drop_str) {
+ ret = av_expr_parse(&s->drop_pexpr, s->drop_str,
+ var_names, NULL, NULL, NULL, NULL, 0, ctx);
+ if (ret < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for drop: %s\n", s->drop_str);
+ return ret;
+ }
+ }
+
+ s->var_values[VAR_TB] = ctx->time_base_out.den ? av_q2d(ctx->time_base_out) : 0;
+ s->var_values[VAR_NOPTS] = AV_NOPTS_VALUE;
+ s->var_values[VAR_STARTPTS] = AV_NOPTS_VALUE;
+ s->var_values[VAR_STARTDTS] = AV_NOPTS_VALUE;
+ s->var_values[VAR_STATE] = 0;
+
+ return 0;
+}
+
+static int noise(AVBSFContext *ctx, AVPacket *pkt)
+{
+ NoiseContext *s = ctx->priv_data;
+ int i, ret, amount, drop;
+ double res;
ret = ff_bsf_get_packet_ref(ctx, pkt);
if (ret < 0)
return ret;
- if (s->dropamount > 0 && s->state % s->dropamount == 0) {
- s->state++;
+ s->var_values[VAR_N] = s->pkt_idx++;
+ s->var_values[VAR_PTS] = pkt->pts;
+ s->var_values[VAR_DTS] = pkt->dts;
+ s->var_values[VAR_DURATION] =
+ s->var_values[VAR_D] = pkt->duration;
+ s->var_values[VAR_SIZE] = pkt->size;
+ s->var_values[VAR_KEY] = !!(pkt->flags & AV_PKT_FLAG_KEY);
+ s->var_values[VAR_POS] = pkt->pos;
+
+ if (s->var_values[VAR_STARTPTS] == AV_NOPTS_VALUE)
+ s->var_values[VAR_STARTPTS] = pkt->pts;
+
+ if (s->var_values[VAR_STARTDTS] == AV_NOPTS_VALUE)
+ s->var_values[VAR_STARTDTS] = pkt->dts;
+
+ res = av_expr_eval(s->amount_pexpr, s->var_values, NULL);
+
+ if (isnan(res))
+ amount = 0;
+ else if (res < 0)
+ amount = (s->state % 10001 + 1);
+ else
+ amount = (int)res;
+
+ if (s->drop_str) {
+ res = av_expr_eval(s->drop_pexpr, s->var_values, NULL);
+
+ if (isnan(res))
+ drop = 0;
+ else if (res < 0)
+ drop = !(s->state % FFABS((int)res));
+ else
+ drop = !!res;
+ }
+
+ av_log(ctx, AV_LOG_VERBOSE, "Stream #%d packet %d pts %"PRId64" - amount %d drop %d\n",
+ pkt->stream_index, (unsigned int)s->var_values[VAR_N], pkt->pts, amount, drop);
+
+ if (s->drop_str && drop) {
+ s->var_values[VAR_STATE] = ++s->state;
av_packet_unref(pkt);
return AVERROR(EAGAIN);
}
- ret = av_packet_make_writable(pkt);
- if (ret < 0) {
- av_packet_unref(pkt);
- return ret;
+ if (amount) {
+ ret = av_packet_make_writable(pkt);
+ if (ret < 0) {
+ av_packet_unref(pkt);
+ return ret;
+ }
}
for (i = 0; i < pkt->size; i++) {
s->state += pkt->data[i] + 1;
- if (s->state % amount == 0)
+ if (amount && s->state % amount == 0)
pkt->data[i] = s->state;
}
+ s->var_values[VAR_STATE] = s->state;
+
return 0;
}
+static void noise_close(AVBSFContext *bsf)
+{
+ NoiseContext *s = bsf->priv_data;
+
+ av_expr_free(s->amount_pexpr);
+ av_expr_free(s->drop_pexpr);
+ s->amount_pexpr = s->drop_pexpr = NULL;
+}
+
#define OFFSET(x) offsetof(NoiseContext, x)
#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_BSF_PARAM)
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 },
+ { "amount", NULL, OFFSET(amount_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
+ { "drop", NULL, OFFSET(drop_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
+ { "dropamount", NULL, OFFSET(drop_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
{ NULL },
};
@@ -86,5 +213,7 @@ const AVBitStreamFilter ff_noise_bsf = {
.name = "noise",
.priv_data_size = sizeof(NoiseContext),
.priv_class = &noise_class,
+ .init = noise_init,
+ .close = noise_close,
.filter = noise,
};
diff --git a/tests/fate/matroska.mak b/tests/fate/matroska.mak
index ca7193a055..b57765280a 100644
--- a/tests/fate/matroska.mak
+++ b/tests/fate/matroska.mak
@@ -88,7 +88,7 @@ FATE_MATROSKA_FFMPEG_FFPROBE-$(call ALLYES, FILE_PROTOCOL MXF_DEMUXER \
MATROSKA_MUXER MATROSKA_DEMUXER \
FRAMECRC_MUXER PIPE_PROTOCOL) \
+= fate-matroska-mastering-display-metadata
-fate-matroska-mastering-display-metadata: CMD = transcode mxf $(TARGET_SAMPLES)/mxf/Meridian-Apple_ProResProxy-HDR10.mxf matroska "-map 0 -map 0:0 -c:v:0 copy -c:v:1 ffv1 -c:a:0 copy -bsf:a:0 noise=amount=3 -filter:a:1 aresample -c:a:1 pcm_s16be -bsf:a:1 noise=dropamount=4" "-map 0 -c copy" "" "-show_entries stream_side_data_list:stream=index,codec_name"
+fate-matroska-mastering-display-metadata: CMD = transcode mxf $(TARGET_SAMPLES)/mxf/Meridian-Apple_ProResProxy-HDR10.mxf matroska "-map 0 -map 0:0 -c:v:0 copy -c:v:1 ffv1 -c:a:0 copy -bsf:a:0 noise=amount=3 -filter:a:1 aresample -c:a:1 pcm_s16be -bsf:a:1 noise=amount=-1:dropamount=-4" "-map 0 -c copy" "" "-show_entries stream_side_data_list:stream=index,codec_name"
# This test tests remuxing annex B H.264 into Matroska. It also tests writing
# the correct interlaced flags and overriding the sample aspect ratio, leading
--
2.32.0
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