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authorJörn Heusipp <osmanx@problemloesungsmaschine.de>2018-02-21 12:11:48 +0100
committerMichael Niedermayer <michael@niedermayer.cc>2018-03-20 22:59:40 +0100
commitf6ea397d0ae4e4188e90deecbcffd1cf5419c110 (patch)
tree6256685c8001c9aed2c6ec4464f4fe9c6cb6935a
parent81b0d591d690f518c01c45d7ce20fdca1de80d80 (diff)
downloadffmpeg-f6ea397d0ae4e4188e90deecbcffd1cf5419c110.tar.gz
avformat/libopenmpt: Probe file format from file data if possible
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'. libopenmpt probing adds about 5%..10% cpu time (depending on precise usage pattern and host CPU and compiler version used for libopenmpt) compared to all current internal FFmpeg probing functions combined in tools/probetest for all of its module formats combined (currently 41 modules formats in libopenmpt 0.3.4 and 234 file formats in FFmpeg). Signed-off-by: Jörn Heusipp <osmanx@problemloesungsmaschine.de> Reviewed-by: Josh de Kock <josh@itanimul.li> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
-rw-r--r--libavformat/libopenmpt.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/libavformat/libopenmpt.c b/libavformat/libopenmpt.c
index 5efbdc4273..0fff702a36 100644
--- a/libavformat/libopenmpt.c
+++ b/libavformat/libopenmpt.c
@@ -218,6 +218,62 @@ static int read_seek_openmpt(AVFormatContext *s, int stream_idx, int64_t ts, int
return 0;
}
+static int probe_openmpt_extension(AVProbeData *p)
+{
+ const char *ext;
+ if (p->filename) {
+ ext = strrchr(p->filename, '.');
+ if (ext && strlen(ext + 1) > 0) {
+ ext++; /* skip '.' */
+ if (openmpt_is_extension_supported(ext) == 1)
+ return AVPROBE_SCORE_EXTENSION;
+ }
+ }
+ return 0;
+}
+
+static int read_probe_openmpt(AVProbeData *p)
+{
+#if OPENMPT_API_VERSION_AT_LEAST(0,3,0)
+ int probe_result;
+ 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_SUCCESS) {
+ /* As probing here relies on code external to FFmpeg, do not return
+ * AVPROBE_SCORE_MAX in order to reduce the impact in the rare
+ * cases of false positives.
+ */
+ return AVPROBE_SCORE_MIME + 1;
+ } else if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_WANTMOREDATA) {
+ if (probe_openmpt_extension(p) > 0) {
+ return AVPROBE_SCORE_RETRY;
+ } else {
+ 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.
+ */
+ return AVPROBE_SCORE_RETRY / 2;
+ } 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.
+ */
+ return 0;
+ }
+ }
+ } else if (probe_result == OPENMPT_PROBE_FILE_HEADER_RESULT_FAILURE) {
+ return 0;
+ }
+ }
+#endif
+ /* for older libopenmpt, fall back to file extension probing */
+ return probe_openmpt_extension(p);
+}
+
static const AVClass class_openmpt = {
.class_name = "libopenmpt",
.item_name = av_default_item_name,
@@ -229,6 +285,7 @@ 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,