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Commit a392aea6 authored by Harish Mahendrakar's avatar Harish Mahendrakar
Browse files

Speed up SniffMidi() by parsing the initial bytes of the header 

SniffMidi() was creating a MidiEngine() instance which in turn was
using a WatchDog timer to abort if the operation took longer than
10 seconds. In some cases, SniffMidi() was consuming more than 10 seconds.

This is now optimized by parsing a few initial bytes to identify
different types of midi files.

Bug: 359920208
Test: atest CtsMediaPlayerTestCases \
 CtsMediaExtractorTestCases \
 CtsMediaAudioTestCases:MidiSoloTest \
 CtsMediaAudioTestCases:SoundPoolMidiTest \
 CtsMediaV2TestCases:ExtractorTest \
 CtsMediaV2TestCases:ExtractorUnitTest

Change-Id: Ibf1e922d6de32ab6f2fbd8178843603a9bf72100
parent 2abffc64

media/module/extractors/Android.bp

+18 −0
Original line number Diff line number Diff line
@@ -68,3 +68,21 @@ cc_defaults { 
        ],

    },

}



aconfig_declarations {

    name: "android.media.extractor.flags-aconfig",

    package: "com.android.media.extractor.flags",

    container: "com.android.media",

    srcs: ["extractor.aconfig"],

}



cc_aconfig_library {

    name: "android.media.extractor.flags-aconfig-cc",

    aconfig_declarations: "android.media.extractor.flags-aconfig",

    host_supported: true,

    min_sdk_version: "29",

    apex_available: [

        "//apex_available:platform",

        "com.android.media",

    ],

}

media/module/extractors/extractor.aconfig

0 → 100644
+13 −0
Original line number Diff line number Diff line 
# Media Extractor flags.

#

# !!! Please add flags in alphabetical order. !!!

package: "com.android.media.extractor.flags"

container: "com.android.media"



flag {

    name: "extractor_sniff_midi_optimizations"

    is_exported: true

    namespace: "media_extractor"

    description: "Enable SniffMidi optimizations."

    bug: "359920208"

}

media/module/extractors/fuzzers/Android.bp

+7 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ package { 
    // to get the below license kinds:

    //   SPDX-license-identifier-Apache-2.0

    default_applicable_licenses: ["frameworks_av_license"],

    default_team: "trendy_team_android_media_solutions_playback",

}



cc_defaults {
@@ -301,12 +302,18 @@ cc_fuzz { 
    ],



    static_libs: [

        "android.media.extractor.flags-aconfig-cc",

        "libaconfig_storage_read_api_cc",

        "libsonivox",

        "libmedia_midiiowrapper",

        "libmidiextractor",

        "libwatchdog",

    ],



    shared_libs: [

        "server_configurable_flags",

    ],



    dictionary: "midi_extractor_fuzzer.dict",



    host_supported: true,

media/module/extractors/midi/Android.bp

+3 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ cc_library { 
    ],



    static_libs: [

        "android.media.extractor.flags-aconfig-cc",

        "libaconfig_storage_read_api_cc",

        "libmedia_midiiowrapper",

        "libsonivoxwithoutjet",

        "libstagefright_foundation",
@@ -40,6 +42,7 @@ cc_library { 


    shared_libs: [

        "libbase",

        "server_configurable_flags",

    ],



    host_supported: true,

media/module/extractors/midi/MidiExtractor.cpp

+131 −3
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 


#include "MidiExtractor.h"



#include <com_android_media_extractor_flags.h>

#include <media/MidiIoWrapper.h>

#include <media/stagefright/foundation/ADebug.h>

#include <media/stagefright/MediaBufferGroup.h>
@@ -323,10 +324,97 @@ media_status_t MidiExtractor::getMetaData(AMediaFormat *meta) 
    return AMediaFormat_copy(meta, mFileMetadata);

}



// Sniffer

static bool startsWith(const uint8_t *buf, size_t size, const char *pattern, size_t patternSize) {

    if (size < patternSize) {

        return false;

    }

    return (memcmp(buf, pattern, patternSize) == 0);

}



bool SniffMidi(CDataSource *source, float *confidence)

{

static bool isValidMThd(const uint8_t *buf, size_t size) {

    return startsWith(buf, size, "MThd", 4);

}



static bool isValidXmf(const uint8_t *buf, size_t size) {

    return startsWith(buf, size, "XMF_", 4);

}



static bool isValidImelody(const uint8_t *buf, size_t size) {

    return startsWith(buf, size, "BEGIN:IMELODY", 13);

}



static bool isValidRtttl(const uint8_t *buf, size_t size) {

    #define RTTTL_MAX_TITLE_LEN 32

    // rtttl starts with the following:

    // <title>:<type>=<value>

    //

    // Where:

    // - <title>: Up to 32 characters

    // - <type>: Single character indicating:

    //     'd' for duration

    //     'o' for octave

    //     'b' for beats per minute

    // - <value>: Corresponding value for the type

    if (size < 4) {

        return false;

    }

    for (size_t i = 0; i < RTTTL_MAX_TITLE_LEN && i < size; i++) {

        if (buf[i] == ':') {

            if (i < (size - 3) && buf[i + 2] == '=') {

                return true;

            }

            break;

        }

    }

    return false;

}



static bool isValidOta(const uint8_t *buf, size_t size) {

    #define OTA_RINGTONE 0x25

    #define OTA_SOUND 0x1d

    #define OTA_UNICODE 0x22



    // ota starts with the following:

    // <cmdLen><cmd1><cmd2>..<cmdN>

    //

    // Where:

    // - <cmdLen>: Single character command length

    // - <cmd1>: Single character (OTA_RINGTONE << 1)

    // - <cmd2>: Single character (OTA_SOUND << 1) or (OTA_UNICODE << 1)

    //           and so on with last cmd being (0x1d << 1)



    if (size < 3) {

        return false;

    }



    uint8_t cmdLen = buf[0];

    if (cmdLen < 2) {

        return false;

    }



    if ((buf[1] >> 1) != OTA_RINGTONE) {

        return false;

    }

    cmdLen--;



    size_t i = 2;

    while(cmdLen && i < size) {

        switch(buf[i] >> 1) {

            case OTA_SOUND:

                return true;

            case OTA_UNICODE:

                break;

            default:

                return false;

        }

        cmdLen--;

        i++;

    }



    return false;

}



bool SniffMidiLegacy(CDataSource *source, float *confidence) {

    MidiEngine p(source, NULL, NULL);

    if (p.initCheck() == OK) {

        *confidence = 0.8;
@@ -335,7 +423,47 @@ bool SniffMidi(CDataSource *source, float *confidence) 
    }

    ALOGV("SniffMidi: no");

    return false;

}



bool SniffMidiEfficiently(CDataSource *source, float *confidence) {

    uint8_t header[128];

    int filled = source->readAt(source->handle, 0, header, sizeof(header));



    if (isValidMThd(header, filled)) {

        *confidence = 0.80;

        ALOGV("SniffMidi: yes, MThd");

        return true;

    }

    if (isValidXmf(header, filled)) {

        *confidence = 0.80;

        ALOGV("SniffMidi: yes, XMF_");

        return true;

    }

    if (isValidImelody(header, filled)) {

        *confidence = 0.80;

        ALOGV("SniffMidi: yes, imelody");

        return true;

    }

    if (isValidRtttl(header, filled)) {

        *confidence = 0.80;

        ALOGV("SniffMidi: yes, rtttl");

        return true;

    }

    if (isValidOta(header, filled)) {

        *confidence = 0.80;

        ALOGV("SniffMidi: yes, ota");

        return true;

    }

    ALOGV("SniffMidi: no");

    return false;

}



// Sniffer

bool SniffMidi(CDataSource *source, float *confidence) {

    if(com::android::media::extractor::flags::extractor_sniff_midi_optimizations()) {

        return SniffMidiEfficiently(source, confidence);

    }

    return SniffMidiLegacy(source, confidence);

}



static const char *extensions[] = {