AndroidVDA by using Android's MediaCodec API.

media/base/android/media_codec_bridge.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/android/media_codec_bridge.h"
+
+#include <jni.h>
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_array.h"
+#include "base/android/jni_string.h"
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "base/stringprintf.h"
+
+#include "jni/MediaFormat_jni.h"
+#include "jni/MediaCodec_jni.h"
+
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::ScopedJavaLocalRef;
+
+namespace {
+
+static jclass g_MediaCodecBufferInfo_clazz = NULL;
+
+static const char kMediaCodecBufferInfoClassPath[] =
+    "android/media/MediaCodec$BufferInfo";
+
+static bool MediaCodecBufferInfo_RegisterNativesImpl(JNIEnv* env) {
+  g_MediaCodecBufferInfo_clazz = reinterpret_cast<jclass>(env->NewGlobalRef(
+      base::android::GetUnscopedClass(env, kMediaCodecBufferInfoClassPath)));
+  base::android::CheckException(env);
+  return true;
+}
+
+static void GetBufferInfo(JNIEnv* env, jobject buffer_info, int* offset,
+                          int* size, int64* presentation_time, int* flags) {
+  static jfieldID offset_id =
+      env->GetFieldID(g_MediaCodecBufferInfo_clazz, "offset", "I");
+  static jfieldID size_id =
+      env->GetFieldID(g_MediaCodecBufferInfo_clazz, "size", "I");
+  static jfieldID presentation_time_id =
+      env->GetFieldID(g_MediaCodecBufferInfo_clazz, "presentationTimeUs", "J");
+  static jfieldID flags_id =
+      env->GetFieldID(g_MediaCodecBufferInfo_clazz, "flags", "I");
+
+  *offset = static_cast<int>(env->GetIntField(buffer_info, offset_id));
+  *size = static_cast<int>(env->GetIntField(buffer_info, size_id));
+  *presentation_time =
+      static_cast<int64>(env->GetLongField(buffer_info, presentation_time_id));
+  *flags = static_cast<int>(env->GetIntField(buffer_info, flags_id));

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

are the static_cast<int>'s really necessary?

[dwkang1, 2013/02/04 14:08:26]

Removed.

[dwkang1, 2013/02/04 14:08:26]

Removed.

+}
+
+static base::subtle::AtomicWord g_MediaCodecBufferInfo_Constructor = 0;
+static ScopedJavaLocalRef<jobject> Java_MediaCodecBufferInfo_Constructor(
+    JNIEnv* env) {
+  /* Must call RegisterNativesImpl()  */
+  DCHECK(g_MediaCodecBufferInfo_clazz);
+  jmethodID method_id =
+      base::android::MethodID::LazyGet<base::android::MethodID::TYPE_INSTANCE>(
+      env, g_MediaCodecBufferInfo_clazz,
+      "<init>", "()V",
+      &g_MediaCodecBufferInfo_Constructor);
+
+  jobject ret = env->NewObject(g_MediaCodecBufferInfo_clazz, method_id);
+  base::android::CheckException(env);
+  return ScopedJavaLocalRef<jobject>(env, ret);
+}
+
+void RegisterNativesIfNeeded(JNIEnv* env) {
+  static bool jni_initialized = false;
+  if (!jni_initialized) {

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

This is both racy and unreadable :)

You have:

static bool inited = false;
if (!inited) {  // Two threads can get here at the same time!  Only
function-static init is guaranteed atomicity!
  inited = ...;
  DCHECK(inited);
}


which can be written more readably as:
static bool inited = ...;
DCHECK(inited);

[dwkang1, 2013/02/04 14:08:26]

Thanks for the advise. btw, do you have any reference about atomicity of the
second approach?

+    jni_initialized = (
+        JNI_MediaCodec::RegisterNativesImpl(env)
+        && MediaCodecBufferInfo_RegisterNativesImpl(env)

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

operator goes on previous line (here and elsewhere)

[dwkang1, 2013/02/04 14:08:26]

Done.

+        && JNI_MediaFormat::RegisterNativesImpl(env));
+    DCHECK(jni_initialized);
+  }
+}
+}  // namespace
+
+namespace media {
+
+typedef struct {

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

This is C++; 
typedef struct { ... } Name;
is more idiomatically typed as:
struct Name { ... };

[dwkang1, 2013/02/04 14:08:26]

Done.

+  MediaCodecBridge::Codec codec_type_;
+    const char* mime_type_;

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

de-indent 2 spaces

[dwkang1, 2013/02/04 14:08:26]

Done.

+} CodecMapEntry;
+
+static
+const CodecMapEntry kCodecMimeTypeTable[] = {
+    { MediaCodecBridge::AUDIO_MPEG, "audio/mpeg" },
+    { MediaCodecBridge::VIDEO_H264, "video/avc" },
+    { MediaCodecBridge::VIDEO_VP8, "video/x-vnd.on2.vp8" },
+    { MediaCodecBridge::UNKNOWN, NULL },
+};
+
+#define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0])))

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

Drop in favor of arraysize()
https://code.google.com/p/chromium/codesearch#chrome/src/base/basictypes.h&q=...

[dwkang1, 2013/02/04 14:08:26]

Thanks for the link.

+
+static
+const char* CodecToMimeType(const MediaCodecBridge::Codec codec) {
+    for (int i = 0; i < NELEM(kCodecMimeTypeTable); ++i) {
+        if (kCodecMimeTypeTable[i].codec_type_ == codec) {
+            return kCodecMimeTypeTable[i].mime_type_;
+        }
+    }
+    return NULL;
+}

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

l.86-109 can be replaced with the 9 lines:
static const char* CodecToMimeType(const MediaCodecBridge::Codec codec) {
  switch (codec) {
    case MediaCodecBridge::AUDIO_MPEG: return "audio/mpeg";
    case MediaCodecBridge::VIDEO_H264: return "video/avc";
    case MediaCodecBridge::VIDEO_VP8: return "video/x-vnd.on2.vp8";
    default:
      return NULL;
  }
}

Keep it simple :)

[dwkang1, 2013/02/04 14:08:26]

Done.

+
+MediaCodecBridge::MediaCodecBridge(const Codec codec) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+  RegisterNativesIfNeeded(env);
+  DCHECK(CodecToMimeType(codec));
+
+  ScopedJavaLocalRef<jstring> j_type =
+      ConvertUTF8ToJavaString(env, CodecToMimeType(codec));
+
+  ScopedJavaLocalRef<jobject> tmp(
+      JNI_MediaCodec::Java_MediaCodec_createDecoderByType(env, j_type.obj()));
+  DCHECK(!tmp.is_null());
+  j_media_codec_.Reset(tmp);
+}
+
+MediaCodecBridge::~MediaCodecBridge() {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  JNI_MediaCodec::Java_MediaCodec_release(env, j_media_codec_.obj());
+}
+
+void MediaCodecBridge::ConfigureAudio(
+    const Codec codec, int sample_rate, int channel_count) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+  DCHECK(CodecToMimeType(codec));
+
+  ScopedJavaLocalRef<jstring> j_mime =
+      ConvertUTF8ToJavaString(env, CodecToMimeType(codec));
+  ScopedJavaLocalRef<jobject> j_format(
+      JNI_MediaFormat::Java_MediaFormat_createAudioFormat(
+          env, j_mime.obj(), sample_rate, channel_count));
+  DCHECK(!j_format.is_null());
+
+  JNI_MediaCodec::Java_MediaCodec_configure(
+      env, j_media_codec_.obj(), j_format.obj(), NULL, NULL, 0);
+
+  JNI_MediaCodec::Java_MediaCodec_start(env, j_media_codec_.obj());
+}
+
+void MediaCodecBridge::ConfigureVideo(
+    const Codec codec, const gfx::Size& size, jobject surface) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+  DCHECK(CodecToMimeType(codec));
+
+  ScopedJavaLocalRef<jstring> j_mime =
+      ConvertUTF8ToJavaString(env, CodecToMimeType(codec));
+  ScopedJavaLocalRef<jobject> j_format(
+      JNI_MediaFormat::Java_MediaFormat_createVideoFormat(
+          env, j_mime.obj(), size.width(), size.height()));
+  DCHECK(!j_format.is_null());
+
+  JNI_MediaCodec::Java_MediaCodec_configure(
+      env, j_media_codec_.obj(), j_format.obj(), surface, NULL, 0);
+
+  JNI_MediaCodec::Java_MediaCodec_start(env, j_media_codec_.obj());
+}
+
+void MediaCodecBridge::Flush() {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  JNI_MediaCodec::Java_MediaCodec_flush(env, j_media_codec_.obj());
+}
+
+void MediaCodecBridge::Stop() {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  JNI_MediaCodec::Java_MediaCodec_stop(env, j_media_codec_.obj());
+}
+
+void MediaCodecBridge::GetOutputFormat(int* format, int* width, int* height) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  ScopedJavaLocalRef<jobject> j_format(
+     JNI_MediaCodec::Java_MediaCodec_getOutputFormat(
+         env, j_media_codec_.obj()));
+  if (!j_format.is_null()) {
+    ScopedJavaLocalRef<jstring> j_key_format =
+        ConvertUTF8ToJavaString(env, "color-format");
+    *format = static_cast<int>(JNI_MediaFormat::Java_MediaFormat_getInteger(
+        env, j_format.obj(), j_key_format.obj()));
+
+    ScopedJavaLocalRef<jstring> j_key_width =
+        ConvertUTF8ToJavaString(env, "width");
+    *width = static_cast<int>(JNI_MediaFormat::Java_MediaFormat_getInteger(
+        env, j_format.obj(), j_key_width.obj()));
+
+    ScopedJavaLocalRef<jstring> j_key_height =
+        ConvertUTF8ToJavaString(env, "height");
+    *height = static_cast<int>(JNI_MediaFormat::Java_MediaFormat_getInteger(
+        env, j_format.obj(), j_key_height.obj()));
+  }
+}
+
+void MediaCodecBridge::QueueInputBuffer(
+    int index, int offset, int size, int64 presentation_time_us, int flags) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  JNI_MediaCodec::Java_MediaCodec_queueInputBuffer(
+      env, j_media_codec_.obj(),
+      static_cast<jint>(index), static_cast<jint>(offset),
+      static_cast<jint>(size), static_cast<jlong>(presentation_time_us),
+      static_cast<jint>(flags));
+}
+
+int MediaCodecBridge::DequeueInputBuffer(int64 timeout_us) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  return JNI_MediaCodec::Java_MediaCodec_dequeueInputBuffer(
+      env, j_media_codec_.obj(), static_cast<jlong>(timeout_us));
+}
+
+int MediaCodecBridge::DequeueOutputBuffer(
+    int64 timeout_us, int* offset, int* size, int64* presentation_time_us,
+    int* flags) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  ScopedJavaLocalRef<jobject> j_info(
+      Java_MediaCodecBufferInfo_Constructor(env));
+  jint j_buffer = JNI_MediaCodec::Java_MediaCodec_dequeueOutputBuffer(
+      env, j_media_codec_.obj(), j_info.obj(), static_cast<jlong>(timeout_us));
+
+  if (j_buffer >= 0) {
+    GetBufferInfo(env, j_info.obj(), offset, size, presentation_time_us, flags);
+  }
+  return static_cast<int>(j_buffer);

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

drop the cast? (here and elsewhere)

[dwkang1, 2013/02/04 14:08:26]

Done.

+}
+
+void MediaCodecBridge::ReleaseOutputBuffer(int index, bool render) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  JNI_MediaCodec::Java_MediaCodec_releaseOutputBuffer(
+      env, j_media_codec_.obj(), static_cast<jint>(index),
+      static_cast<jboolean>(render));
+}
+
+int MediaCodecBridge::GetInputBuffers() {

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

Why do you need to expose this as a public API of MCB?  ISTM you can simply
always call it immediately after start() returns, as an impl detail, no?

[dwkang1, 2013/02/04 14:08:26]

According to the api doc we need to call getOutputBuffers() when
INFO_OUTPUT_BUFFERS_CHANGED is returned. So GOB() should be public. In GIB()
case, we can make it private and call it in Start(), but it doesn't look
consistent to me. WDYT?

+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  j_input_buffers_.Reset(
+      JNI_MediaCodec::Java_MediaCodec_getInputBuffers(
+          env, j_media_codec_.obj()));
+
+  return env->GetArrayLength(j_input_buffers_.obj());
+}
+
+int MediaCodecBridge::GetOutputBuffers() {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  j_output_buffers_.Reset(
+      JNI_MediaCodec::Java_MediaCodec_getOutputBuffers(
+          env, j_media_codec_.obj()));
+
+  return env->GetArrayLength(j_output_buffers_.obj());
+}
+
+void MediaCodecBridge::PutToInputBuffer(
+    int index, const uint8* data, int size) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  ScopedJavaLocalRef<jobject> j_buffer(
+      env, env->GetObjectArrayElement(j_input_buffers_.obj(), index));
+
+  uint8* direct_buffer =
+      static_cast<uint8*>(env->GetDirectBufferAddress(j_buffer.obj()));
+  memcpy(direct_buffer, data, size);

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

I think you missed my comment about |size| being too big.
You need to get the buffer's capacity first and ensure you're not going to be
writing over random memory with this call.
I suspect you'll need to make this method return bool instead of void and force
callers to make sure they haven't overflowed.

[dwkang1, 2013/01/29 03:58:48]

Sorry for the missing your previous comment. Will fix in this next patch set!

[dwkang1, 2013/02/04 14:08:26]

Changed to return # of bytes written.

+}
+
+void MediaCodecBridge::GetFromOutputBuffer(
+    int index, int offset, uint8* data, int size) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  ScopedJavaLocalRef<jobject> j_buffer(
+      env, env->GetObjectArrayElement(j_output_buffers_.obj(), index));
+
+  uint8* direct_buffer =
+      static_cast<uint8*>(env->GetDirectBufferAddress(j_buffer.obj()));
+  memcpy(data, direct_buffer + offset, size);

[Ami GONE FROM CHROMIUM, 2013/01/28 19:49:45]

Ditto you need some way to guarantee the requested size isn't going to be
reading random memory.
(but, again, I think you can drop this bit of API)

[dwkang1, 2013/02/04 14:08:26]

Dropped. :)

+}
+
+}  // namespace media
+