extractor: Fast-track the stream analysis if we already have a skip condition

The sniffer already has an abort clause if the container is identified
as MPEG4 and the media source is caching (HTTP, typically). If we figure
this out early, there's no need to drill down into the individual streams,
and we can skip the deeper stream analysis, saving somewhere between 5 and
15 seconds in the identification process.

Change-Id: I64d33dc22262dd389e48b5f07047a8a1908f4ff3

diff --git a/libstagefright/FFmpegExtractor/FFmpegExtractor.cpp b/libstagefright/FFmpegExtractor/FFmpegExtractor.cpp
index f37884b..f320c92 100644 (file)
--- a/libstagefright/FFmpegExtractor/FFmpegExtractor.cpp
+++ b/libstagefright/FFmpegExtractor/FFmpegExtractor.cpp
@@ -1767,7 +1767,7 @@ static const char *findMatchingContainer(const char *name)
        return container;
 }
 
-static const char *SniffFFMPEGCommon(const char *url, float *confidence)
+static const char *SniffFFMPEGCommon(const char *url, float *confidence, bool fastMPEG4)
 {
        int err = 0;
        size_t i = 0;
@@ -1790,6 +1790,13 @@ static const char *SniffFFMPEGCommon(const char *url, float *confidence)
        }
 
        err = avformat_open_input(&ic, url, NULL, NULL);
+
+        if (ic->iformat != NULL && fastMPEG4 &&
+              !strcasecmp(findMatchingContainer(ic->iformat->name),
+                MEDIA_MIMETYPE_CONTAINER_MPEG4)) {
+            return MEDIA_MIMETYPE_CONTAINER_MPEG4;
+        }
+
        if (err < 0) {
         ALOGE("%s: avformat_open_input failed, err:%s", url, av_err2str(err));
                goto fail;
@@ -1841,7 +1848,7 @@ static const char *BetterSniffFFMPEG(const sp<DataSource> &source,
        // pass the addr of smart pointer("source")
        snprintf(url, sizeof(url), "android-source:%p", source.get());
 
-       ret = SniffFFMPEGCommon(url, confidence);
+       ret = SniffFFMPEGCommon(url, confidence, (source->flags() & DataSource::kIsCachingDataSource));
        if (ret) {
                meta->setString("extended-extractor-url", url);
        }
@@ -1865,7 +1872,7 @@ static const char *LegacySniffFFMPEG(const sp<DataSource> &source,
        // pass the addr of smart pointer("source") + file name
        snprintf(url, sizeof(url), "android-source:%p|file:%s", source.get(), uri.string());
 
-       ret = SniffFFMPEGCommon(url, confidence);
+       ret = SniffFFMPEGCommon(url, confidence, false);
        if (ret) {
                meta->setString("extended-extractor-url", url);
        }