[FFmpeg-cvslog] avformat/mpsubdec: Remove floating point usage
Michael Niedermayer
git at videolan.org
Thu Aug 29 17:22:39 EEST 2019
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Jul 30 19:11:27 2019 +0200| [e0c973e5bea94dc70baf20d5a36e123b1ca1f901] | committer: Michael Niedermayer
avformat/mpsubdec: Remove floating point usage
This makes the code bitexact between platforms.
Intermediate timestamps between frames are preserved.
The timebase is simplified.
Rounding differs from doubles in cases where timestamps/durations
are "funny"
Suggested-by: jb
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e0c973e5bea94dc70baf20d5a36e123b1ca1f901
---
libavformat/mpsubdec.c | 84 ++++++++++++++++++++++++++++++++---------
tests/ref/fate/sub-mpsub-frames | 4 +-
2 files changed, 69 insertions(+), 19 deletions(-)
diff --git a/libavformat/mpsubdec.c b/libavformat/mpsubdec.c
index a8217a4a61..3d8dcb35c2 100644
--- a/libavformat/mpsubdec.c
+++ b/libavformat/mpsubdec.c
@@ -27,6 +27,8 @@
#include "internal.h"
#include "subtitles.h"
+#define TSBASE 10000000
+
typedef struct {
FFDemuxSubtitlesQueue q;
} MPSubContext;
@@ -51,21 +53,55 @@ static int mpsub_probe(const AVProbeData *p)
return 0;
}
+static int parse_line(const char *line, int64_t *value, int64_t *value2)
+{
+ int vi, p1, p2;
+
+ for (vi = 0; vi < 2; vi++) {
+ long long intval, fracval;
+ int n = av_sscanf(line, "%lld%n.%lld%n", &intval, &p1, &fracval, &p2);
+ if (n <= 0 || intval < INT64_MIN / TSBASE || intval > INT64_MAX / TSBASE)
+ return AVERROR_INVALIDDATA;
+
+ intval *= TSBASE;
+
+ if (n == 2) {
+ if (fracval < 0)
+ return AVERROR_INVALIDDATA;
+ for (;p2 - p1 < 7 + 1; p1--)
+ fracval *= 10;
+ for (;p2 - p1 > 7 + 1; p1++)
+ fracval /= 10;
+ if (intval > 0) intval += fracval;
+ else intval -= fracval;
+ line += p2;
+ } else
+ line += p1;
+
+ *value = intval;
+
+ value = value2;
+ }
+
+ return 0;
+}
+
static int mpsub_read_header(AVFormatContext *s)
{
MPSubContext *mpsub = s->priv_data;
AVStream *st;
AVBPrint buf;
- AVRational pts_info = (AVRational){ 100, 1 }; // ts based by default
+ AVRational pts_info = (AVRational){ TSBASE, 1 }; // ts based by default
int res = 0;
- int multiplier = 100;
- double current_pts = 0;
+ int64_t current_pts = 0;
+ int i;
+ int common_factor = 0;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
while (!avio_feof(s->pb)) {
char line[1024];
- double start, duration;
+ int64_t start, duration;
int fps, len = ff_get_line(s->pb, line, sizeof(line));
if (!len)
@@ -75,34 +111,48 @@ static int mpsub_read_header(AVFormatContext *s)
if (sscanf(line, "FORMAT=%d", &fps) == 1 && fps > 3 && fps < 100) {
/* frame based timing */
- pts_info = (AVRational){ fps, 1 };
- multiplier = 1;
- } else if (sscanf(line, "%lf %lf", &start, &duration) == 2) {
+ pts_info = (AVRational){ TSBASE * fps, 1 };
+ } else if (parse_line(line, &start, &duration) >= 0) {
AVPacket *sub;
const int64_t pos = avio_tell(s->pb);
ff_subtitles_read_chunk(s->pb, &buf);
if (buf.len) {
- double ts = current_pts + start*multiplier;
sub = ff_subtitles_queue_insert(&mpsub->q, buf.str, buf.len, 0);
if (!sub) {
res = AVERROR(ENOMEM);
goto end;
}
- if (!isfinite(ts) || ts < INT64_MIN || ts > INT64_MAX) {
- avpriv_request_sample(s, "Invalid ts\n");
- } else
- sub->pts = (int64_t)ts;
- if (!isfinite(duration) || duration * multiplier > INT_MAX || duration < 0) {
- avpriv_request_sample(s, "Invalid duration\n");
- } else
- sub->duration = (int)(duration * multiplier);
- current_pts += (start + duration) * multiplier;
+ if ( current_pts < 0 && start < INT64_MIN - current_pts
+ || current_pts > 0 && start > INT64_MAX - current_pts) {
+ res = AVERROR_INVALIDDATA;
+ goto end;
+ }
+ sub->pts = current_pts + start;
+ if (duration < 0 || sub->pts > INT64_MAX - duration) {
+ res = AVERROR_INVALIDDATA;
+ goto end;
+ }
+ sub->duration = duration;
+
+ common_factor = av_gcd(duration, common_factor);
+ common_factor = av_gcd(sub->pts, common_factor);
+
+ current_pts = sub->pts + duration;
sub->pos = pos;
}
}
}
+ if (common_factor > 1) {
+ common_factor = av_gcd(pts_info.num, common_factor);
+ for (i = 0; i < mpsub->q.nb_subs; i++) {
+ mpsub->q.subs[i].pts /= common_factor;
+ mpsub->q.subs[i].duration /= common_factor;
+ }
+ pts_info.num /= common_factor;
+ }
+
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
diff --git a/tests/ref/fate/sub-mpsub-frames b/tests/ref/fate/sub-mpsub-frames
index 64528ec70e..17695787be 100644
--- a/tests/ref/fate/sub-mpsub-frames
+++ b/tests/ref/fate/sub-mpsub-frames
@@ -10,5 +10,5 @@ Style: Default,Arial,16,&Hffffff,&Hffffff,&H0,&H0,0,0,0,0,100,100,0,0,1,1,0,2,10
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
-Dialogue: 0,0:00:01.00,0:00:02.48,Default,,0,0,0,,Start at 1sec,\Nlast 1.5 seconds
-Dialogue: 0,0:00:02.52,0:00:11.52,Default,,0,0,0,,One frame later,\Nduring 9 seconds
+Dialogue: 0,0:00:01.00,0:00:02.50,Default,,0,0,0,,Start at 1sec,\Nlast 1.5 seconds
+Dialogue: 0,0:00:02.54,0:00:11.54,Default,,0,0,0,,One frame later,\Nduring 9 seconds
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