Some samples would be nice. The commit messages mentions many millions
of files, which we obviously can't fit into the FATE suite. But one or
two would be nice
Spotify comments
----------------
None
/Tomas
From 30e364f3b8d382f2ec59254ca41fc8a25f1133ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Peter=20Zeb=C3=BChr?= <pet...@spotify.com>
Date: Tue, 21 Nov 2023 14:16:49 +0100
Subject: [PATCH 15/15] Make mime-type award a bonus probe score
This changes the default behaviour of ffmpeg where content-type headers
on an input gives an absolut probe score (of 75) to instead give a bonus
score (of 30). This gives the probe a better chance to arrive at the
correct format by (hopefully) giving a large enough bonus to push edge
cases in the right direction (MPEG-PS vs MP3, I am looking at you) while
also not adversly punishing clearer cases (raw ADTS marked as
"audio/mpeg" for example).
This patch was regression tested against 20 million recent podcast
submissions (after content-type propagation was added to
original-storage), and 50k Juno vodcasts submissions (dito). No adverse
effects observed (but the bonus may still need tweaking if other edge
cases are detected in production).
---
libavformat/avformat.h | 2 +-
libavformat/format.c | 8 ++++----
libavformat/libopenmpt.c | 2 +-
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index cedfd82170..35cef585f9 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -459,7 +459,7 @@ typedef struct AVProbeData {
#define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
#define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
-#define AVPROBE_SCORE_MIME 75 ///< score for file mime type
+#define AVPROBE_SCORE_MIME_BONUS 30 ///< score added for matching mime type
#define AVPROBE_SCORE_MAX 100 ///< maximum score
#define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
diff --git a/libavformat/format.c b/libavformat/format.c
index e65a6fc05e..71018ea6ab 100644
--- a/libavformat/format.c
+++ b/libavformat/format.c
@@ -212,10 +212,10 @@ const AVInputFormat *av_probe_input_format3(const AVProbeData *pd,
score = AVPROBE_SCORE_EXTENSION;
}
if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
- if (AVPROBE_SCORE_MIME > score) {
- av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, score, AVPROBE_SCORE_MIME);
- score = AVPROBE_SCORE_MIME;
- }
+ int old_score = score;
+ score += AVPROBE_SCORE_MIME_BONUS;
+ if (score > AVPROBE_SCORE_MAX) score = AVPROBE_SCORE_MAX;
+ av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, old_score, score);
}
if (score > score_max) {
score_max = score;
diff --git a/libavformat/libopenmpt.c b/libavformat/libopenmpt.c
index 736af7caf2..dee975c9c2 100644
--- a/libavformat/libopenmpt.c
+++ b/libavformat/libopenmpt.c
@@ -244,7 +244,7 @@ static int read_probe_openmpt(const AVProbeData *p)
* AVPROBE_SCORE_MAX in order to reduce the impact in the rare
* cases of false positives.
*/
- return AVPROBE_SCORE_MIME + 1;
+ return (AVPROBE_SCORE_MAX * 3) / 4 + 1;
} else if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_WANTMOREDATA) {
if (probe_openmpt_extension(p) > 0) {
return AVPROBE_SCORE_RETRY;
--
2.39.2
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