本文介绍iOS下使用FFmpeg+x264进行软编码。
x264是一个开源的H.264/MPEG-4 AVC视频编码函数库,我们可以直接使用x264的API进行编码,也可以将x264编译到FFmpeg中,使用FFmpeg提供的API进行编码。
一、编译x264
1、下载gas-preprocessor文件:
- https://github.com/libav/gas-preprocessor
- 将里面的gas-preprocessor.pl拷贝到/usr/local/bin目录下
- 修改文件权限:chmod 777 /usr/local/bin/gas-preprocessor.pl
2、下载x264源码:
- [https://www.videolan.org/developers/x264.html]
3、下载x264编译脚本文件:
- https://www.videolan.org/developers/x264.html
4、将源码与脚本放在一起:
-
新建一个文件夹,将编译脚本build-x264.sh与x264源码文件夹放入这个新建文件夹中,并将x264文件夹(x264-snapshot-xxxx)改名为"x264"
5、修改权限、执行脚本:
- sudo chmod u+x build-x264.sh
- sudo ./build-x264.sh
- 编译过程中会生成scratch-x264文件夹与thin-x264文件夹
- 编译完成最终会生成"x264-iOS"文件夹
6、编译遇到的问题:
No working C compiler found.
可能是xcode路径问题,终端输入命令:
sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer/Found no assembler,Minimum version is yasm-x.x.x
或Found no assembler,Minimum version is nasm-x.x.x
或Found yasm x.x.x.xxxx,Minimum version is yasm-x.x.x
或Found nasm x.x.x.xxxx,Minimum version is nasm-x.x.x
原因是没有安装yasm/nasm或yasm/nasm版本太低,需要重新安装yasm/nasm。
安装yasm/nasm可通过Homebrew安装,Homebrew下载地址:https://brew.sh/
Homebrew安装yasm命令:brew install yasm
Homebrew安装nasm命令:brew install nasm如果已经安装了yasm/nasm并且是最新版本,仍然提示上面的问题,那么可能是yasm/nasm安装的路径没有识别到,
which yasm
或which nasm
查看下路径,并将最新版本的yasm/nasm拷贝到此目录下,如果使用"sudo"命令也没有权限,那么需要按照下面的步骤关闭rootless:
(1) 关机、重启进入恢复模式
重启系统。按住Command + R进入恢复模式, 在菜单中打开Terminal
(2) 关闭rootless
输入:csrutil disable,重启设备
(3) 拷贝完成,重新打开rootless如果编译i386遇到No working C compiler found
可以直接将i386略过编译,即编译脚本中ARCHS="arm64 x86_64 i386 armv7 armv7s"
将i386去掉重新编译,或终端输入./build-x264.sh arm64 x86_64 armv7 armv7s
进行编译
二、编译FFmpeg+x264
1、下载FFmpeg编译脚本:
- https://github.com/kewlbear/FFmpeg-iOS-build-script
2、x264修改
- 将build-ffmpeg.sh中的
#X264=`pwd`/fat-x264
注释去掉,即X264=`pwd`/fat-x264
- 将x264编译出来的lib库文件夹放入ffmpeg编译脚本的文件夹中,并改名为"fat-x264"
3、编译FFmpeg
- ./build-ffmpeg.sh
注:如果出现i386问题,脚本中同样将ARCHS中的i386去掉
ARCHS="arm64 armv7 x86_64"
- 编译完成,在目录下会生成"FFmpeg-iOS"文件夹
三、编码实现
1、将编译好的FFmpeg-iOS
与x264-iOS
导入工程中
2、导入系统库
- 导入
、libz.1.2.5.tbd、libbz2.1.0.tbd、libiconv.2.4.0.tbd等系统库
可参考:https://www.jianshu.com/p/5d20e2a50faa
3、Code
- X264Encoder.h
#import
#import
NS_ASSUME_NONNULL_BEGIN
@interface X264Encoder : NSObject
@property (assign, nonatomic) CGSize videoSize;
@property (assign, nonatomic) CGFloat frameRate;
@property (assign, nonatomic) CGFloat maxKeyframeInterval;
@property (assign, nonatomic) CGFloat bitrate;
@property (strong, nonatomic) NSString *profileLevel;
+ (instancetype)defaultX264Encoder;
- (instancetype)initX264Encoder:(CGSize)videoSize
frameRate:(NSUInteger)frameRate
maxKeyframeInterval:(CGFloat)maxKeyframeInterval
bitrate:(NSUInteger)bitrate
profileLevel:(NSString *)profileLevel;
- (void)encoding:(CVPixelBufferRef)pixelBuffer timestamp:(CGFloat)timestamp;
- (void)teardown;
@end
NS_ASSUME_NONNULL_END
- X264Encoder.m
#import "X264Encoder.h"
#ifdef __cplusplus
extern "C" {
#endif
#include
#include
#include
#include
#ifdef __cplusplus
};
#endif
@implementation X264Encoder
{
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVPacket packet;
AVFrame *pFrame;
int pictureSize;
int frameCounter;
int frameWidth;
int frameHeight;
}
+ (instancetype)defaultX264Encoder
{
X264Encoder *x264encoder = [[X264Encoder alloc] initX264Encoder:CGSizeMake(720, 1280) frameRate:30 maxKeyframeInterval:25 bitrate:1024*1000 profileLevel:@""];
return x264encoder;
}
- (instancetype)initX264Encoder:(CGSize)videoSize
frameRate:(NSUInteger)frameRate
maxKeyframeInterval:(CGFloat)maxKeyframeInterval
bitrate:(NSUInteger)bitrate
profileLevel:(NSString *)profileLevel
{
self = [super init];
if (self) {
_videoSize = videoSize;
_frameRate = frameRate;
_maxKeyframeInterval = maxKeyframeInterval;
_bitrate = bitrate;
_profileLevel = profileLevel;
[self setupEncoder];
}
return self;
}
- (void)setupEncoder
{
avcodec_register_all();
frameCounter = 0;
frameWidth = self.videoSize.width;
frameHeight = self.videoSize.height;
// Param that must set
pCodecCtx = avcodec_alloc_context3(pCodec);
pCodecCtx->codec_id = AV_CODEC_ID_H264;
pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
pCodecCtx->width = frameWidth;
pCodecCtx->height = frameHeight;
pCodecCtx->time_base.num = 1;
pCodecCtx->time_base.den = self.frameRate;
pCodecCtx->bit_rate = self.bitrate;
pCodecCtx->gop_size = self.maxKeyframeInterval;
pCodecCtx->qmin = 10;
pCodecCtx->qmax = 51;
AVDictionary *param = NULL;
if(pCodecCtx->codec_id == AV_CODEC_ID_H264) {
av_dict_set(¶m, "preset", "slow", 0);
av_dict_set(¶m, "tune", "zerolatency", 0);
}
pCodec = avcodec_find_encoder(pCodecCtx->codec_id);
if (!pCodec) {
NSLog(@"Can not find encoder!");
}
if (avcodec_open2(pCodecCtx, pCodec, ¶m) < 0) {
NSLog(@"Failed to open encoder!");
}
pFrame = av_frame_alloc();
pFrame->width = frameWidth;
pFrame->height = frameHeight;
pFrame->format = AV_PIX_FMT_YUV420P;
avpicture_fill((AVPicture *)pFrame, NULL, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
pictureSize = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
av_new_packet(&packet, pictureSize);
}
- (void)encoding:(CVPixelBufferRef)pixelBuffer timestamp:(CGFloat)timestamp
{
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
UInt8 *pY = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0);
UInt8 *pUV = (UInt8 *)CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1);
size_t width = CVPixelBufferGetWidth(pixelBuffer);
size_t height = CVPixelBufferGetHeight(pixelBuffer);
size_t pYBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
size_t pUVBytes = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);
UInt8 *pYUV420P = (UInt8 *)malloc(width * height * 3 / 2);
UInt8 *pU = pYUV420P + (width * height);
UInt8 *pV = pU + (width * height / 4);
for(int i = 0; i < height; i++) {
memcpy(pYUV420P + i * width, pY + i * pYBytes, width);
}
for(int j = 0; j < height / 2; j++) {
for(int i = 0; i < width / 2; i++) {
*(pU++) = pUV[i<<1];
*(pV++) = pUV[(i<<1) + 1];
}
pUV += pUVBytes;
}
pFrame->data[0] = pYUV420P;
pFrame->data[1] = pFrame->data[0] + width * height;
pFrame->data[2] = pFrame->data[1] + (width * height) / 4;
pFrame->pts = frameCounter;
int got_picture = 0;
if (!pCodecCtx) {
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
return;
}
int ret = avcodec_encode_video2(pCodecCtx, &packet, pFrame, &got_picture);
if(ret < 0) {
NSLog(@"Failed to encode!");
}
if (got_picture == 1) {
NSLog(@"Succeed to encode frame: %5d\tsize:%5d", frameCounter, packet.size);
frameCounter++;
av_free_packet(&packet);
}
free(pYUV420P);
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
}
- (void)teardown
{
avcodec_close(pCodecCtx);
av_free(pFrame);
pCodecCtx = NULL;
pFrame = NULL;
}
@end
- use
- (void)initX264Encoder
{
dispatch_sync(encodeQueue, ^{
self->x264encoder = [X264Encoder defaultX264Encoder];
});
}
- (void)teardown
{
dispatch_sync(encodeQueue, ^{
[self->x264encoder teardown];
});
}
- (void)videoWithSampleBuffer:(CMSampleBufferRef)sampleBuffer
{
dispatch_sync(encodeQueue, ^{
if (self->isRecording) {
CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CMTime ptsTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBuffer);
CGFloat pts = CMTimeGetSeconds(ptsTime);
[self->x264encoder encoding:pixelBuffer timestamp:pts];
}
});
}
以上,则实现了iOS下使用FFmpeg+x264进行软编码的整个流程。
demo:https://github.com/XuningZhai/VideoEncode_x264