Fix MP4 sniffing for very short files

The sniffer sniffs boxes at the start of the file to try and determine
whether the file is fragmented. However, if the file is extremely short
then it's possible that sniffing will try and read beyond the end of
the file, resulting i EOFException being thrown.

In general it's OK for sniffing to throw EOFException if the file is
not of the correct type. The problem in this case is that EOFException
can be thrown for an actual MP4 file, due to the sniffer continuing up
sniff atoms up to bytesToSearch in case the file is fragmented.

PiperOrigin-RevId: 325205389

RELEASENOTES.md

@@ -4,8 +4,10 @@
 
 *   Fix distorted playback of floating point audio when samples exceed the
     `[-1, 1]` nominal range.
-*   MP4: Add support for `piff` and `isml` brands
+*   MP4:
+    *   Add support for `piff` and `isml` brands
         ([#7584](https://github.com/google/ExoPlayer/issues/7584)).
+    *   Fix playback of very short MP4 files.
 *   FMP4: Fix `saiz` and `senc` sample count checks, resolving a "length
     mismatch" `ParserException` when playing certain protected FMP4 streams
     ([#7592](https://github.com/google/ExoPlayer/issues/7592)).

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/Sniffer.java

@@ -103,7 +103,12 @@ import java.io.IOException;
       // Read an atom header.
       int headerSize = Atom.HEADER_SIZE;
       buffer.reset(headerSize);
-      input.peekFully(buffer.data, 0, headerSize);
+      boolean success =
+          input.peekFully(buffer.data, 0, headerSize, /* allowEndOfInput= */ true);
+      if (!success) {
+        // We've reached the end of the file.
+        break;
+      }
       long atomSize = buffer.readUnsignedInt();
       int atomType = buffer.readInt();
       if (atomSize == Atom.DEFINES_LARGE_SIZE) {