MediaExtractor: set buffer offset/limit in readSampleData

also fix setting offset/limit in MediaCodec's getBuffer.

Bug: 13008204
Change-Id: Iadf0f006cfccc2546971cc5384058e1a2721780b

media/java/android/media/MediaCodec.java

@@ -1157,6 +1157,9 @@ final public class MediaCodec {
      * @deprecated Use the new {@link #getInputBuffer} method instead
      * each time an input buffer is dequeued.
      *
+     * <b>Note:</b>As of API 21, dequeued input buffers are
+     * automatically {@link java.nio.Buffer#clear cleared}.
+     *
      * @throws IllegalStateException if not in the Executing state.
      * @throws MediaCodec.CodecException upon codec error.
      */
@@ -1180,6 +1183,10 @@ final public class MediaCodec {
      * each time an output buffer is dequeued.  This method is not
      * supported if codec is configured in asynchronous mode.
      *
+     * <b>Note:</b>As of API 21, the position and limit of output
+     * buffers that are dequeued will be set to the valid data
+     * range.
+     *
      * @throws IllegalStateException if not in the Executing state,
      *         or codec is configured in asynchronous mode.
      * @throws MediaCodec.CodecException upon codec error.
@@ -1213,8 +1220,8 @@ final public class MediaCodec {
     }
 
     /**
-     * Returns a cleared, writable ByteBuffer object for a dequeued
-     * input buffer index to contain the input data.
+     * Returns a {@link java.nio.Buffer#clear cleared}, writable ByteBuffer
+     * object for a dequeued input buffer index to contain the input data.
      *
      * After calling this method any ByteBuffer or Image object
      * previously returned for the same input index MUST no longer

media/java/android/media/MediaExtractor.java

@@ -297,8 +297,12 @@ final public class MediaExtractor {
 
     /**
      * Retrieve the current encoded sample and store it in the byte buffer
-     * starting at the given offset. Returns the sample size (or -1 if
-     * no more samples are available).
+     * starting at the given offset.
+     * <p>
+     * <b>Note:</b>As of API 21, on success the position and limit of
+     * {@code byteBuf} is updated to point to the data just read.
+     * @param byteBuf the destination byte buffer
+     * @return the sample size (or -1 if no more samples are available).
      */
     public native int readSampleData(ByteBuffer byteBuf, int offset);
 
@@ -316,7 +320,10 @@ final public class MediaExtractor {
 
     // Keep these in sync with their equivalents in NuMediaExtractor.h
     /**
-     * The sample is a sync sample
+     * The sample is a sync sample (or in {@link MediaCodec}'s terminology
+     * it is a key frame.)
+     *
+     * @see MediaCodec#BUFFER_FLAG_KEY_FRAME
      */
     public static final int SAMPLE_FLAG_SYNC      = 1;
 

media/jni/android_media_MediaCodec.cpp

@@ -448,14 +448,14 @@ status_t JMediaCodec::getBuffer(
     jobject me = env->CallObjectMethod(
             byteBuffer, orderID, nativeByteOrderObj);
     env->DeleteLocalRef(me);
-    me = env->CallObjectMethod(
-            byteBuffer, positionID,
-            input ? 0 : buffer->offset());
-    env->DeleteLocalRef(me);
     me = env->CallObjectMethod(
             byteBuffer, limitID,
             input ? buffer->capacity() : (buffer->offset() + buffer->size()));
     env->DeleteLocalRef(me);
+    me = env->CallObjectMethod(
+            byteBuffer, positionID,
+            input ? 0 : buffer->offset());
+    env->DeleteLocalRef(me);
     me = NULL;
 
     env->DeleteLocalRef(nativeByteOrderObj);

media/jni/android_media_MediaExtractor.cpp

@@ -36,6 +36,8 @@
 #include <media/stagefright/MetaData.h>
 #include <media/stagefright/NuMediaExtractor.h>
 
+#include <nativehelper/ScopedLocalRef.h>
+
 #include "android_util_Binder.h"
 
 namespace android {
@@ -206,12 +208,12 @@ status_t JMediaExtractor::readSampleData(
     size_t dstSize;
     jbyteArray byteArray = NULL;
 
-    if (dst == NULL) {
-        jclass byteBufClass = env->FindClass("java/nio/ByteBuffer");
-        CHECK(byteBufClass != NULL);
+    ScopedLocalRef<jclass> byteBufClass(env, env->FindClass("java/nio/ByteBuffer"));
+    CHECK(byteBufClass.get() != NULL);
 
+    if (dst == NULL) {
         jmethodID arrayID =
-            env->GetMethodID(byteBufClass, "array", "()[B");
+            env->GetMethodID(byteBufClass.get(), "array", "()[B");
         CHECK(arrayID != NULL);
 
         byteArray =
@@ -251,6 +253,24 @@ status_t JMediaExtractor::readSampleData(
 
     *sampleSize = buffer->size();
 
+    jmethodID positionID = env->GetMethodID(
+            byteBufClass.get(), "position", "(I)Ljava/nio/Buffer;");
+
+    CHECK(positionID != NULL);
+
+    jmethodID limitID = env->GetMethodID(
+            byteBufClass.get(), "limit", "(I)Ljava/nio/Buffer;");
+
+    CHECK(limitID != NULL);
+
+    jobject me = env->CallObjectMethod(
+            byteBuf, limitID, offset + *sampleSize);
+    env->DeleteLocalRef(me);
+    me = env->CallObjectMethod(
+            byteBuf, positionID, offset);
+    env->DeleteLocalRef(me);
+    me = NULL;
+
     return OK;
 }