From ecc3459990f2871fd907f96fe66362b8fea41bd8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Peter=20Zeb=C3=BChr?= Date: Tue, 21 Nov 2023 14:16:49 +0100 Subject: [PATCH 8/8] 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 6abdb6d480..498c557a3c 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; -- 2.39.5