我使用ffmpeg库来解码,缩放和重新编码MPEG传输流内的视频。我刚刚从源代码重新编译为v3.3.2,并从旧的avcodec_decode_video2()API更改为新的发送/接收API。FFMPEG解码太慢(avcodec_send_packet()/ avcodec_receive_frame())
旧的和新的API都非常缓慢地解码视频。
25 fps视频=每40ms 1帧。但是,我看到每帧需要70至120毫秒才能解码。这是一个文件翻译器,因此需要它比实时更快地运行。
代码大纲如下。任何人有关于如何提高解码速度的任何想法?还有一些关于已弃用的avcodec_decode_video2()
缓慢的帖子;这些都没有解决。新的API不跑得更快......
gettimeofday(&tv1, NULL);
int rc = av_read_frame(pFormatContext, pESPacket);
gettimeofday(&tv2, NULL);
int ret = avcodec_send_packet(pDecoderContext, pESPacket);
if (ret < 0)
continue;
ret = avcodec_receive_frame(pDecoderContext, pFrameDec);
if (ret != 0)
{
printf("avcodec_receive_frame error: %d\n", ret);
continue;
}
gettimeofday(&tv3, 0);
u_long twoMinusOne = (tv2.tv_sec - tv1.tv_sec) * 1000000 + tv2.tv_usec - tv1.tv_usec;
u_long threeMinusTwo = (tv3.tv_sec - tv2.tv_sec) * 1000000 + tv3.tv_usec - tv2.tv_usec;
size_t pktSize = mPacketQueue.getTsPktListSize();
printf(" DECODE ReadFrame %lu usec, DecodeVideo %lu usec. mTsPacketList %u items\n", twoMinusOne, threeMinusTwo, pktSize);
transcodeFrame(pFrameDec);
// Scale and re-encode //
-- call avscale to downsample
-- call avcodec_encode_video2() to encode
一些输出上酷睿双核运行3.2 GHz的32位元的CentOS
DECODE ReadFrame 6 usec, DecodeVideo 154273 usec.
Dump mpFrameEnc with DateTime:
AVFrame Info frame 720 X 406. PTS = 305700353 PKT_PTS = 305700353 Linesize[0]=720. Linesize[1]=360. Linesize[2]=360.
Time taken to ENCODE video frame = 3685 usec. Scaling time 4 usec
DECODE ReadFrame 8 usec, DecodeVideo 128203 usec.
Time taken to ENCODE video frame = 3724 usec. Scaling time 3 usec
DECODE ReadFrame 8 usec, DecodeVideo 69321 usec.
Time taken to ENCODE video frame = 3577 usec. Scaling time 3 usec
FFMPEG版本
测试6.
bin/ffmpeg
ffmpeg version 3.3.2 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-11)
configuration: --prefix=/mnt/swdevel/DVStor/source_build/ext/ffmpeg-build --libdir=/mnt/swdevel/DVStor/source_build/ext/ffmpeg-build/lib3p_build --shlibdir=/mnt/swdevel/DVStor/source_build/ext/ffmpeg-build/lib3p_build --disable-static --enable-shared --disable-cuda --disable-cuvid --disable-nvenc --enable-libx264 --enable-gpl --extra-cflags=-I/usr/local/include/libx264
libavutil 55. 58.100/55. 58.100
libavcodec 57. 89.100/57. 89.100
libavformat 57. 71.100/57. 71.100
libavdevice 57. 6.100/57. 6.100
libavfilter 6. 82.100/6. 82.100
libswscale 4. 6.100/4. 6.100
libswresample 2. 7.100/2. 7.100
libpostproc 54. 5.100/54. 5.100
Hyper fast Audio and Video encoder
你是否在同一个线程上抓包,解码帧,缩放和编码? – WLGfx
一个线程用TS数据包填充一个队列,这在代码中没有显示。第二个线程使用AVIO提供read_frame,读取帧,解码并编码。但真正的问题在于,当一帧画面时,解码器需要很长时间。 – Danny
你好,丹尼!现在我面临着解码ffmpeg缓慢的问题。我很好奇你是否找到了解决方案?如果是这样,请让我知道。谢谢 –