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ffmpeg: reallocate output buffer dynamically

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With FFmpeg we can't determine size of output buffer ahead of time for all codecs,
so we need to reallocate it when needed instead of simply failing.
This commit is contained in:
Alexey Rochev 2023-10-30 19:21:49 +03:00 committed by tonihei
parent 3a527a888a
commit adee4626d3
4 changed files with 90 additions and 19 deletions
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20
libraries/decoder/src/main/java/androidx/media3/decoder/SimpleDecoderOutputBuffer.java
View File

@ -16,6 +16,7 @@
package androidx.media3.decoder;
import androidx.annotation.Nullable;
import androidx.media3.common.util.Assertions;
import androidx.media3.common.util.UnstableApi;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
@ -49,6 +50,25 @@ public class SimpleDecoderOutputBuffer extends DecoderOutputBuffer {
return data;
}
/**
* Reallocates the buffer with new size
* Existing data between beginning of the buffer and {@link ByteBuffer#limit} is copied to the new buffer,
* and {@link ByteBuffer#position} is preserved. {@link ByteBuffer#limit} is set to the new size.
* @param newSize New size of buffer.
* @return The {@link #data} buffer, for convenience.
*/
public ByteBuffer grow(int newSize) {
Assertions.checkNotNull(data);
final ByteBuffer newData = ByteBuffer.allocateDirect(newSize).order(ByteOrder.nativeOrder());
final int restorePosition = data.position();
data.position(0);
newData.put(data);
newData.position(restorePosition);
newData.limit(newSize);
data = newData;
return newData;
}
@Override
public void clear() {
super.clear();

5
libraries/decoder_ffmpeg/proguard-rules.txt
View File

@ -4,3 +4,8 @@
-keepclasseswithmembernames class * {
native <methods>;
}
# This method is called from native code
-keep class androidx.media3.decoder.ffmpeg.FfmpegAudioDecoder {
private java.nio.ByteBuffer growOutputBuffer(androidx.media3.decoder.SimpleDecoderOutputBuffer, int);
}

28
libraries/decoder_ffmpeg/src/main/java/androidx/media3/decoder/ffmpeg/FfmpegAudioDecoder.java
View File

@ -32,9 +32,8 @@ import java.util.List;
/* package */ final class FfmpegAudioDecoder
extends SimpleDecoder<DecoderInputBuffer, SimpleDecoderOutputBuffer, FfmpegDecoderException> {
// Output buffer sizes when decoding PCM mu-law streams, which is the maximum FFmpeg outputs.
private static final int OUTPUT_BUFFER_SIZE_16BIT = 65536;
private static final int OUTPUT_BUFFER_SIZE_32BIT = OUTPUT_BUFFER_SIZE_16BIT * 2;
private static final int INITIAL_OUTPUT_BUFFER_SIZE_16BIT = 65535;
private static final int INITIAL_OUTPUT_BUFFER_SIZE_32BIT = INITIAL_OUTPUT_BUFFER_SIZE_16BIT * 2;
private static final int AUDIO_DECODER_ERROR_INVALID_DATA = -1;
private static final int AUDIO_DECODER_ERROR_OTHER = -2;
@ -42,7 +41,7 @@ import java.util.List;
private final String codecName;
@Nullable private final byte[] extraData;
private final @C.PcmEncoding int encoding;
private final int outputBufferSize;
private int outputBufferSize;
private long nativeContext; // May be reassigned on resetting the codec.
private boolean hasOutputFormat;
@ -64,7 +63,7 @@ import java.util.List;
codecName = Assertions.checkNotNull(FfmpegLibrary.getCodecName(format.sampleMimeType));
extraData = getExtraData(format.sampleMimeType, format.initializationData);
encoding = outputFloat ? C.ENCODING_PCM_FLOAT : C.ENCODING_PCM_16BIT;
outputBufferSize = outputFloat ? OUTPUT_BUFFER_SIZE_32BIT : OUTPUT_BUFFER_SIZE_16BIT;
outputBufferSize = outputFloat ? INITIAL_OUTPUT_BUFFER_SIZE_32BIT : INITIAL_OUTPUT_BUFFER_SIZE_16BIT;
nativeContext =
ffmpegInitialize(codecName, extraData, outputFloat, format.sampleRate, format.channelCount);
if (nativeContext == 0) {
@ -107,8 +106,9 @@ import java.util.List;
}
ByteBuffer inputData = Util.castNonNull(inputBuffer.data);
int inputSize = inputData.limit();
ByteBuffer outputData = outputBuffer.init(inputBuffer.timeUs, outputBufferSize);
int result = ffmpegDecode(nativeContext, inputData, inputSize, outputData, outputBufferSize);
outputBuffer.init(inputBuffer.timeUs, outputBufferSize);
int result = ffmpegDecode(nativeContext, inputData, inputSize, outputBuffer, outputBuffer.data, outputBufferSize);
if (result == AUDIO_DECODER_ERROR_OTHER) {
return new FfmpegDecoderException("Error decoding (see logcat).");
} else if (result == AUDIO_DECODER_ERROR_INVALID_DATA) {
@ -135,11 +135,19 @@ import java.util.List;
}
hasOutputFormat = true;
}
outputData.position(0);
outputData.limit(result);
outputBuffer.data.position(0);
outputBuffer.data.limit(result);
return null;
}
// Called from native code
/** @noinspection unused*/
private ByteBuffer growOutputBuffer(SimpleDecoderOutputBuffer outputBuffer, int requiredSize) {
// Use it for new buffer so that hopefully we won't need to reallocate again
outputBufferSize = requiredSize;
return outputBuffer.grow(requiredSize);
}
@Override
public void release() {
super.release();
@ -221,7 +229,7 @@ import java.util.List;
int rawChannelCount);
private native int ffmpegDecode(
long context, ByteBuffer inputData, int inputSize, ByteBuffer outputData, int outputSize);
long context, ByteBuffer inputData, int inputSize, SimpleDecoderOutputBuffer decoderOutputBuffer, ByteBuffer outputData, int outputSize);
private native int ffmpegGetChannelCount(long context);

54
libraries/decoder_ffmpeg/src/main/jni/ffmpeg_jni.cc
View File

@ -35,6 +35,8 @@ extern "C" {
#define LOG_TAG "ffmpeg_jni"
#define LOGE(...) \
((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__))
#define LOGD(...) \
((void)__android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__))
#define LIBRARY_FUNC(RETURN_TYPE, NAME, ...) \
extern "C" { \
@ -67,6 +69,8 @@ static const AVSampleFormat OUTPUT_FORMAT_PCM_FLOAT = AV_SAMPLE_FMT_FLT;
static const int AUDIO_DECODER_ERROR_INVALID_DATA = -1;
static const int AUDIO_DECODER_ERROR_OTHER = -2;
static jmethodID growOutputBufferMethod;
/**
* Returns the AVCodec with the specified name, or NULL if it is not available.
*/
@ -81,13 +85,21 @@ AVCodecContext *createContext(JNIEnv *env, AVCodec *codec, jbyteArray extraData,
jboolean outputFloat, jint rawSampleRate,
jint rawChannelCount);
struct GrowOutputBufferCallback {
uint8_t *operator()(int requiredSize) const;
JNIEnv *env;
jobject thiz;
jobject decoderOutputBuffer;
};
/**
* Decodes the packet into the output buffer, returning the number of bytes
* written, or a negative AUDIO_DECODER_ERROR constant value in the case of an
* error.
*/
int decodePacket(AVCodecContext *context, AVPacket *packet,
uint8_t *outputBuffer, int outputSize);
uint8_t *outputBuffer, int outputSize, GrowOutputBufferCallback growBuffer);
/**
* Transforms ffmpeg AVERROR into a negative AUDIO_DECODER_ERROR constant value.
@ -107,6 +119,17 @@ void releaseContext(AVCodecContext *context);
jint JNI_OnLoad(JavaVM *vm, void *reserved) {
JNIEnv *env;
if (vm->GetEnv(reinterpret_cast<void **>(&env), JNI_VERSION_1_6) != JNI_OK) {
LOGE("JNI_OnLoad: GetEnv failed");
return -1;
}
jclass clazz = env->FindClass("androidx/media3/decoder/ffmpeg/FfmpegAudioDecoder");
if (!clazz) {
LOGE("JNI_OnLoad: FindClass failed");
return -1;
}
growOutputBufferMethod = env->GetMethodID(clazz, "growOutputBuffer","(Landroidx/media3/decoder/SimpleDecoderOutputBuffer;I)Ljava/nio/ByteBuffer;");
if (!growOutputBufferMethod) {
LOGE("JNI_OnLoad: GetMethodID failed");
return -1;
}
avcodec_register_all();
@ -138,12 +161,12 @@ AUDIO_DECODER_FUNC(jlong, ffmpegInitialize, jstring codecName,
}
AUDIO_DECODER_FUNC(jint, ffmpegDecode, jlong context, jobject inputData,
jint inputSize, jobject outputData, jint outputSize) {
jint inputSize, jobject decoderOutputBuffer, jobject outputData, jint outputSize) {
if (!context) {
LOGE("Context must be non-NULL.");
return -1;
}
if (!inputData || !outputData) {
if (!inputData || !decoderOutputBuffer || !outputData) {
LOGE("Input and output buffers must be non-NULL.");
return -1;
}
@ -162,7 +185,17 @@ AUDIO_DECODER_FUNC(jint, ffmpegDecode, jlong context, jobject inputData,
packet.data = inputBuffer;
packet.size = inputSize;
return decodePacket((AVCodecContext *)context, &packet, outputBuffer,
outputSize);
outputSize, GrowOutputBufferCallback{env, thiz, decoderOutputBuffer});
}
uint8_t *GrowOutputBufferCallback::operator()(int requiredSize) const {
jobject newOutputData = env->CallObjectMethod(thiz, growOutputBufferMethod, decoderOutputBuffer, requiredSize);
if (env->ExceptionCheck()) {
LOGE("growOutputBuffer() failed");
env->ExceptionDescribe();
return nullptr;
}
return static_cast<uint8_t *>(env->GetDirectBufferAddress(newOutputData));
}
AUDIO_DECODER_FUNC(jint, ffmpegGetChannelCount, jlong context) {
@ -264,7 +297,7 @@ AVCodecContext *createContext(JNIEnv *env, AVCodec *codec, jbyteArray extraData,
}
int decodePacket(AVCodecContext *context, AVPacket *packet,
uint8_t *outputBuffer, int outputSize) {
uint8_t *outputBuffer, int outputSize, GrowOutputBufferCallback growBuffer) {
int result = 0;
// Queue input data.
result = avcodec_send_packet(context, packet);
@ -320,15 +353,20 @@ int decodePacket(AVCodecContext *context, AVPacket *packet,
}
context->opaque = resampleContext;
}
int inSampleSize = av_get_bytes_per_sample(sampleFormat);
int outSampleSize = av_get_bytes_per_sample(context->request_sample_fmt);
int outSamples = swr_get_out_samples(resampleContext, sampleCount);
int bufferOutSize = outSampleSize * channelCount * outSamples;
if (outSize + bufferOutSize > outputSize) {
LOGE("Output buffer size (%d) too small for output data (%d).",
LOGD("Output buffer size (%d) too small for output data (%d), reallocating buffer.",
outputSize, outSize + bufferOutSize);
outputSize = outSize + bufferOutSize;
outputBuffer = growBuffer(outputSize);
if (!outputBuffer) {
LOGE("Failed to reallocate output buffer.");
av_frame_free(&frame);
return AUDIO_DECODER_ERROR_INVALID_DATA;
return AUDIO_DECODER_ERROR_OTHER;
}
}
result = swr_convert(resampleContext, &outputBuffer, bufferOutSize,
(const uint8_t **)frame->data, frame->nb_samples);