When building with libopenmpt 0.3, use the libopenmpt file header probing functions for probing. libopenmpt probing functions are allocation-free and designed to be as fast as possible.
For libopenmpt 0.2, or when libopenmpt 0.3 file header probing cannot probe successfully due to too small probe buffer, test the filename against the file extensions supported by the libopenmpt library that is actually linked, instead of relying on a hard-coded file extension list. File extension testing is also allocation-free and designed to be fast in libopenmpt. Avoiding a hard-coded file extension list is useful because later libopenmpt versions will likely add support for more module file formats. libopenmpt file header probing is tested regularly against the FATE suite and other diverse file collections by libopenmpt upstream in order to avoid false positives. FATE passes with './configure --enable-libopenmpt' as well as with './configure --enable-libopenmpt --enable-libmodplug'. As expected, I did not see any measurable performance difference caused by libopenmpt file header probing when compared to the previous pure file extension based format probing (using the following synthetic test program (which tries to do nothing but exercise file probing) on the complete FATE suite). // find ../fate/ -type f | xargs --no-run-if-empty ./probetest #include <stdio.h> #include "libavformat/avformat.h" #define BUFSIZE 2048 static char buf[BUFSIZE + AVPROBE_PADDING_SIZE]; int main(int argc, const char * * argv) { av_log_set_level(AV_LOG_WARNING); av_register_all(); for (int i = 1; i < argc; ++i) { AVProbeData pd; FILE * f; size_t size; memset(&pd, 0, sizeof(AVProbeData)); pd.filename = argv[i]; memset(buf, 0, sizeof(buf)); f = fopen(pd.filename, "rb"); size = fread(buf, 1, BUFSIZE, f); fclose(f); pd.buf_size = size; av_probe_input_format(&pd, 1); } return 0; } Signed-off-by: Jörn Heusipp <osm...@problemloesungsmaschine.de> --- libavformat/libopenmpt.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/libavformat/libopenmpt.c b/libavformat/libopenmpt.c index 5efbdc4..a663b2e 100644 --- a/libavformat/libopenmpt.c +++ b/libavformat/libopenmpt.c @@ -218,6 +218,64 @@ static int read_seek_openmpt(AVFormatContext *s, int stream_idx, int64_t ts, int return 0; } +static int read_probe_openmpt(AVProbeData * p) +{ + const int score_data = AVPROBE_SCORE_MIME + 1; /* 76 */ + const int score_ext = AVPROBE_SCORE_EXTENSION; /* 50 */ + const int score_ext_retry = AVPROBE_SCORE_RETRY; /* 25 */ + const int score_retry = AVPROBE_SCORE_RETRY / 2; /* 12 */ + const int score_fail = 0; /* 0 */ + + const char *ext; + int probe_result; + int score = score_fail; + + if (p->filename) { + ext = strrchr(p->filename, '.'); + if (ext && strlen(ext + 1) > 0) { + ext++; /* skip '.' */ + if (openmpt_is_extension_supported(ext) == 1) + score = FFMAX(score, score_ext); + } + } + +#if OPENMPT_API_VERSION_AT_LEAST(0,3,0) + if (p->buf && p->buf_size > 0) { + probe_result = openmpt_probe_file_header_without_filesize( + OPENMPT_PROBE_FILE_HEADER_FLAGS_DEFAULT, + p->buf, p->buf_size, + &openmpt_logfunc, NULL, NULL, NULL, NULL, NULL); + if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_FAILURE) { + score = score_fail; + } else if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_SUCCESS) { + score = FFMAX(score, score_data); + } else if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_WANTMOREDATA) { + if (score > score_fail) { + /* known file extension */ + score = FFMAX(score, score_ext_retry); + } else { + /* unknown file extension */ + if (p->buf_size >= openmpt_probe_file_header_get_recommended_size()) { + /* We have already received the recommended amount of data + * and still cannot decide. Return a rather low score. + */ + score = FFMAX(score, score_retry); + } else { + /* The file extension is unknown and we have very few data + * bytes available. libopenmpt cannot decide anything here, + * and returning any score > 0 would result in successfull + * probing of random data. + */ + score = score_fail; + } + } + } + } +#endif + + return score; +} + static const AVClass class_openmpt = { .class_name = "libopenmpt", .item_name = av_default_item_name, @@ -229,6 +287,7 @@ AVInputFormat ff_libopenmpt_demuxer = { .name = "libopenmpt", .long_name = NULL_IF_CONFIG_SMALL("Tracker formats (libopenmpt)"), .priv_data_size = sizeof(OpenMPTContext), + .read_probe = read_probe_openmpt, .read_header = read_header_openmpt, .read_packet = read_packet_openmpt, .read_close = read_close_openmpt, -- 1.9.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel