Android WebRTC 軟體編解碼基于 openH264 和 FFMpeg，但是編譯時默認是不開啟的，想要開啟需要對代碼做一定的增加修改，下面我將所有修改步驟一一列出，
本文基于
webRTC 版本：(https://chromium.googlesource.com/external/webrtc/+/branch-heads/4515)
設備：Mac
虛擬機：Parallels Desktop + Ubuntu 18.4
開始
一：修改 rtc_use_h264 回傳值
路徑：webrtc/src/webrtc.gni ，打開該檔案，修改 rtc_use_h264 屬性為 rtc_use_h264 = true
# rtc_use_h264 =
# proprietary_codecs && !is_android && !is_ios && !(is_win && !is_clang)
rtc_use_h264 = true
二：修改 ffmpeg 相關編譯引數
路徑：webrtc/src/third_party/ffmpeg/ffmpeg_generated.gni
這里需要打開很多與 H264 相關的編譯開關，務必看清楚，不然編譯會報這種錯?
以下是我參考網上各種資料博客整理出來的，只編譯armv7、arm64
#：行
198#
if ((is_mac) || (is_win) || (use_linux_config))
修改
if ((is_mac) || (is_win) || (use_linux_config) || (is_android))
252#
if ((is_mac && ffmpeg_branding == "Chrome") || (is_win && ffmpeg_branding == "Chrome") || (use_linux_config && ffmpeg_branding == "Chrome") || (use_linux_config && ffmpeg_branding == "ChromeOS"))
修改
if ((is_mac && ffmpeg_branding == "Chrome") || (is_win && ffmpeg_branding == "Chrome") || (use_linux_config && ffmpeg_branding == "Chrome") || (use_linux_config && ffmpeg_branding == "ChromeOS") || (is_android))
295#
if ((is_mac && current_cpu == "x64") || (is_win && current_cpu == "x64") || (is_win && current_cpu == "x86") || (use_linux_config && current_cpu == "x64") || (use_linux_config && current_cpu == "x86"))
修改
if ((is_mac && current_cpu == "x64") || (is_win && current_cpu == "x64") || (is_win && current_cpu == "x86") || (use_linux_config && current_cpu == "x64") || (use_linux_config && current_cpu == "x86") || (is_android && current_cpu=="x86") || (is_android && current_cpu=="x64"))
376#
if ((is_mac && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "x86" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x64" && ffmpeg_branding == "ChromeOS") || (use_linux_config && current_cpu == "x86" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x86" && ffmpeg_branding == "ChromeOS"))
修改
if ((is_mac && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "x86" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x64" && ffmpeg_branding == "ChromeOS") || (use_linux_config && current_cpu == "x86" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "x86" && ffmpeg_branding == "ChromeOS") || (is_android && current_cpu == "x64"))
397#
if ((is_mac && current_cpu == "arm64") || (is_win && current_cpu == "arm64") || (use_linux_config && current_cpu == "arm64"))
修改
if ((is_mac && current_cpu == "arm64") || (is_win && current_cpu == "arm64") || (use_linux_config && current_cpu == "arm64") || (is_android && current_cpu == "arm64"))
423#
if ((is_mac && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm64" && ffmpeg_branding == "ChromeOS")
修改
if ((is_mac && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (is_win && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm64" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm64" && ffmpeg_branding == "ChromeOS") || (is_android && current_cpu == "arm64"))
487#
if ((use_linux_config && current_cpu == "arm" && arm_use_neon) || (use_linux_config && current_cpu == "arm"))
修改
if ((use_linux_config && current_cpu == "arm" && arm_use_neon) || (use_linux_config && current_cpu == "arm") || (is_android && current_cpu == "arm"))
527#
if ((use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "ChromeOS") || (use_linux_config && current_cpu == "arm" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && ffmpeg_branding == "ChromeOS"))修改if ((use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "ChromeOS") || (use_linux_config && current_cpu == "arm" && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && ffmpeg_branding == "ChromeOS")|| (is_android && current_cpu == "arm" && arm_use_neon))
545#
if (use_linux_config && current_cpu == "arm" && arm_use_neon)修改if (use_linux_config && current_cpu == "arm" && arm_use_neon || (is_android && current_cpu == "arm" && arm_use_neon))
564#
if ((use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "ChromeOS"))修改if ((use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "Chrome") || (use_linux_config && current_cpu == "arm" && arm_use_neon && ffmpeg_branding == "ChromeOS")||(is_android && current_cpu =="arm" && arm_use_neon))
三：添加靜態編譯
路徑1：webrtc_source/webrtc/src/third_party/ffmpeg/chromium/config/Chromium/android//libavcodec/codec_list.c
添加 &ff_h264_decoder
static const AVCodec * const codec_list[] = { &ff_flac_decoder, &ff_mp3_decoder, &ff_vorbis_decoder, &ff_pcm_alaw_decoder, &ff_pcm_f32le_decoder, &ff_pcm_mulaw_decoder, &ff_pcm_s16be_decoder, &ff_pcm_s16le_decoder, &ff_pcm_s24be_decoder, &ff_pcm_s24le_decoder, &ff_pcm_s32le_decoder, &ff_pcm_u8_decoder, &ff_libopus_decoder, &ff_h264_decoder, NULL };
路徑2：webrtc_source/webrtc/src/third_party/ffmpeg/chromium/config/Chromium/android//libavcodec/parser_list.c
添加 &ff_h264_parser
static const AVCodecParser * const parser_list[] = { &ff_flac_parser, &ff_mpegaudio_parser, &ff_opus_parser, &ff_vorbis_parser, &ff_vp9_parser, &ff_h264_parser, NULL };
四：修改宏定義
路徑：webrtc/src/third_party/ffmpeg/chromium/config/Chromium/android//config.h
搜索 CONFIG_H264_DECODER 將其值由 0 改為 1
#define CONFIG_H264_DECODER 1
五：添加 Licenses
路徑：webrtc/src/tools_webrtc/libs/generate_licenses.py
找到 LIB_TO_LICENSES_DICT 在節點中添加
LIB_TO_LICENSES_DICT = { 'abseil-cpp': ['third_party/abseil-cpp/LICENSE'], ... 'spl_sqrt_floor': ['common_audio/third_party/spl_sqrt_floor/LICENSE'], 'openh264':['third_party/openh264/src/LICENSE'],#添加 'ffmpeg':['third_party/ffmpeg/LICENSE.md']#添加}
六：創建h264_codec.cc
路徑:webrtc/src/sdk/android/src/jni/
在上述路徑新建一個檔案 h264_codec.cc
#include <jni.h>#include "modules/video_coding/codecs/h264/include/h264.h"#include "sdk/android/generated_h264_jni/H264Decoder_jni.h"#include "sdk/android/generated_h264_jni/H264Encoder_jni.h"#include "sdk/android/src/jni/jni_helpers.h"namespace webrtc {namespace jni {static jlong JNI_H264Encoder_CreateEncoder(JNIEnv* jni) { return jlongFromPointer(H264Encoder::Create(cricket::VideoCodec(cricket::kH264CodecName)).release());}static jboolean JNI_H264Encoder_IsSupported(JNIEnv* jni) {return !SupportedH264Codecs().empty();}static jlong JNI_H264Decoder_CreateDecoder(JNIEnv* jni) { return jlongFromPointer(H264Decoder::Create().release());}static jboolean JNI_H264Decoder_IsSupported(JNIEnv* jni) {return !SupportedH264Codecs().empty();}} // namespace jni} // namespace webrtc
七：創建 H264Encode.java 和 H264Decoder.java
路徑：webrtc/src/sdk/android/src/java/org/webrtc/
如果是要編譯成 aar，則在上述目錄增加2個 java檔案，如果是做 NDK 開發自己要修改 webrtc 代碼，上述檔案可以放在你自己的 sdk中，保證目錄是org/webrtc/即可，
H264Decoder.java
package org.webrtc;public class H264Decoder extends WrappedNativeVideoDecoder { @Override public long createNativeVideoDecoder() { return nativeCreateDecoder(); } static native boolean nativeIsSupported(); static native long nativeCreateDecoder();}
H264Encoder.java
package org.webrtc;public class H264Encoder extends WrappedNativeVideoEncoder { @Override public long createNativeVideoEncoder() { return nativeCreateEncoder(); } static native long nativeCreateEncoder(); @Override public boolean isHardwareEncoder() { return false; } static native boolean nativeIsSupported();}
八：修改 java 層軟體編解碼類
找到 SoftwareVideoEncoderFactory.java
public VideoEncoder createEncoder(VideoCodecInfo codecInfo) { String codecName = codecInfo.getName(); if (codecName.equalsIgnoreCase("H264")) {//新增 return new H264Encoder();//新增 }//新增
找到 SoftwareVideoDecoderFactory.java
public VideoDecoder createDecoder(VideoCodecInfo codecInfo) { String codecName = codecInfo.getName(); if (codecName.equalsIgnoreCase(VideoCodecMimeType.H264.toSdpCodecName())){//新增 return new H264Decoder();//新增 }//新增
九：添加 H264 編譯腳本
模仿其他編解碼器寫
路徑：webrtc/src/sdk/android/BUILD.gn
51#
增加：":h264_java",
505#
增加
rtc_android_library("h264_java") { visibility = [ "*" ] sources = [ "api/org/webrtc/H264Decoder.java", "api/org/webrtc/H264Encoder.java", ] deps = [ ":base_java", ":video_api_java", ":video_java", "//rtc_base:base_java", ] }
545#
增加：":h264_java",
860#
增加：
rtc_library("h264_jni") { visibility = [ "*" ] allow_poison = [ "software_video_codecs" ] sources = [ "src/jni/h264_codec.cc" ] deps = [ ":base_jni", ":generated_h264_jni", ":video_jni", "../../modules/video_coding:webrtc_h264", ] }
895#
增加： “:h264_jni”,
1329#
增加：
generate_jni("generated_h264_jni") { sources = [ "api/org/webrtc/H264Decoder.java", "api/org/webrtc/H264Encoder.java", ] namespace = "webrtc::jni" jni_generator_include = "//sdk/android/src/jni/jni_generator_helper.h" }
十：編譯
gn gen out/m93 --args='is_debug=false target_os="android" target_cpu="arm64" rtc_use_h264=true use_custom_libcxx=false'
ninja -C out/release/arm64-v8a
ffmpeg 沖突
這樣編譯出來的靜態庫就包含了ffmpeg，但是是殘缺版的ffmpeg，功能很少，如果自己專案中也有需要用到ffmpeg的地方就很難共用webrtc中的，自己集成的話會報重復定義的沖突，
網上這方面的解決辦法比較少，后來經過幾天的搜索，偶然發現編譯命令有個選項：is_component_ffmpeg設定為false的話就是使用動態庫，這樣的話自己再集成ffmpeg，讓webRTC使用你集成的，這樣就不會有沖突了～
轉載請註明出處，本文鏈接：https://www.uj5u.com/qita/347231.html
標籤：其他