Make limitations of MPEG4Writer explicit

o No more than 2 tracks will be supported
o No more than one video and/or one audio tracks will be supported
o Only take video and/or audio track (for instance, no text tracks)
o If there is no track before start() is called, bail out.

At the same time, make sure the errors from addSource() report to
addTrack(), not to start().

Bug: 7991013

Change-Id: I1ca35aaeb75b5448d75ed2c6c10dd12ecea720ab

1 files changed, 6 insertions, 0 deletions

diff --git a/include/media/stagefright/MPEG4Writer.h b/include/media/stagefright/MPEG4Writer.h
index 3596b38..88df6b0 100644
--- a/include/media/stagefright/MPEG4Writer.h
+++ b/include/media/stagefright/MPEG4Writer.h
@@ -35,7 +35,13 @@ public:
     MPEG4Writer(const char *filename);
     MPEG4Writer(int fd);
 
+    // Limitations
+    // 1. No more than 2 tracks can be added
+    // 2. Only video or audio source can be added
+    // 3. No more than one video and/or one audio source can be added.
     virtual status_t addSource(const sp<MediaSource> &source);
+
+    // Returns INVALID_OPERATION if there is no source or track.
     virtual status_t start(MetaData *param = NULL);
     virtual status_t stop() { return reset(); }
     virtual status_t pause();