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Xvid是基于MPEG4协议的编解码器,x264是基于H.264协议的编码器,ffmpeg集合了各种音频,视频编解码协议,通过设置参数可以完成基于MPEG4,H.264等协议的编解码,现在将其对比结果罗列如下:
1.软件版本:
Xvid:1.2.1
x264:无
ffmpeg:0.5
2. 视频样本 foreman.cif 300帧,大小352x288
3. 所选用编解码器: xvid, x264, ffmpeg
4. 视频流比特率设定 : 1000kbps.
5. 测试结果:
视频编码
编码器 |
编码时间(s) |
视频编码后大小(B) |
比特率(kbps) |
输入视频格式 |
Xvid |
0.98 |
1779213 |
1.18 |
yuyv |
X264 |
2.2 |
1788824 |
1.19 |
yv12 |
ffmpeg(mpeg4协议) |
0.76 |
1754847 |
1.17 |
yv12 |
ffmpeg(h.264协议) |
4.38 |
1741733 |
1.16 |
yv12 |
视频解码
解码器 |
视频所用的编码器 |
解码时间(s) |
输出视频格式 |
|
Xvid |
Xvid |
0.47 |
yuyv |
|
Xvid |
ffmpeg |
0.50 |
yuyv |
|
ffmpeg(mpeg4) |
Xvid |
0.26 |
yv12 |
|
ffmpeg(mpeg4) |
ffmpeg(mpeg4) |
0.31 |
yv12 |
|
ffmpeg(h.264) |
ffmpeg(h.264) |
0.45 |
yv12 |
|
ffmpeg(h.264) |
X264 |
0.78 |
yuyv |
|
6.结论
从以上可以看出:
1). 对于基于MPEG4协议的编解码,ffmpeg的效率都要高于Xvid,主要原因应该是Xvid是以保存视频效果为首要出发点的,其对视频质量的保存应该是做的最好的,这就在一定程度上增加了编解码的复杂性,影响了速度的提升。
2). 对于基于H.264协议的编解码,由于ffmpeg没有本身的h.264编码器,其H.264协议编码是调用x264的编码库来完成的,所以其性能本质上还是x264的,只不过ffmpeg对其进行了封装,但从数据对比可以看出,在本次实验中,ffmpeg调用x264库编码用了4.38秒,远远高于x264的2.2秒,这主要应该是ffmpeg调用x264库时对其进行了不同的参数设置,当然对x264进行接口的封装也会影响一部分性能,但应该不是主要的,主要的应该还是调用x264时,参数有些不同。
所以如果做基于MPEG4的编解码,如果对速度要求高的话,ffmpeg是很好用的工具。
对于H.264协议来说,ffmpeg能很好的解码,而编码的话最好还是要调用x264,因为ffmpeg还没有实现H.264的编码。
附: 各编解码器参数设定:
Xvid:
- xvid_enc_create_obj.version = XVID_VERSION;
- xvid_enc_create_obj.max_key_interval = 100;
- xvid_enc_create_obj.profile = 0xf5;
- xvid_enc_create_obj.fincr = 1;
- xvid_enc_create_obj.fbase = 25;
- xvid_enc_create_obj.num_threads = 0;
- xvid_enc_create_obj.global = 0;
- xvid_enc_create_obj.plugins = plugins;
- xvid_enc_create_obj.num_plugins = 1;
- memset(&plugin_single, 0, sizeof(xvid_plugin_single_t));
- plugin_single.version = XVID_VERSION;
- plugin_single.bitrate = bitrate * 1024;
- plugin_single.reaction_delay_factor = 16;
- plugin_single.averaging_period = 100;
- plugin_single.buffer = 100;
- plugins[0].func = xvid_plugin_single;
- plugins[0].param = &plugin_single;
X264:
- param->cpu = X264_CPU_MMXEXT|X264_CPU_SSE|X264_CPU_SSE2;
- param->i_threads = 1;
- param->b_deterministic = 1;
-
- param->i_csp = X264_CSP_I420;
- param->i_width = 0;
- param->i_height = 0;
- param->vui.i_sar_width = 0;
- param->vui.i_sar_height= 0;
- param->vui.i_overscan = 0;
- param->vui.i_vidformat = 5;
- param->vui.b_fullrange = 0;
- param->vui.i_colorprim = 2;
- param->vui.i_transfer = 2;
- param->vui.i_colmatrix = 2;
- param->vui.i_chroma_loc= 0;
- param->i_fps_num = 25;
- param->i_fps_den = 1;
- param->i_level_idc = -1;
-
- param->i_frame_reference = 1;
- param->i_keyint_max = 250;
- param->i_keyint_min = 25;
- param->i_bframe = 0;
- param->i_scenecut_threshold = 40;
- param->i_bframe_adaptive = X264_B_ADAPT_FAST;
- param->i_bframe_bias = 0;
- param->b_bframe_pyramid = 0;
- param->b_deblocking_filter = 1;
- param->i_deblocking_filter_alphac0 = 0;
- param->i_deblocking_filter_beta = 0;
- param->b_cabac = 1;
- param->i_cabac_init_idc = 0;
- param->rc.i_rc_method = X264_RC_ABR;
- param->rc.i_bitrate = 0;
- param->rc.f_rate_tolerance = 1.0;
- param->rc.i_vbv_max_bitrate = 0;
- param->rc.i_vbv_buffer_size = 0;
- param->rc.f_vbv_buffer_init = 0.9;
- param->rc.i_qp_constant = 26;
- param->rc.f_rf_constant = 0;
- param->rc.i_qp_min = 10;
- param->rc.i_qp_max = 51;
- param->rc.i_qp_step = 4;
- param->rc.f_ip_factor = 1.4;
- param->rc.f_pb_factor = 1.3;
- param->rc.i_aq_mode = X264_AQ_VARIANCE;
- param->rc.f_aq_strength = 1.0;
- param->rc.b_stat_write = 0;
-
- param->rc.b_stat_read = 0;
-
- param->rc.f_qcompress = 0.6;
- param->rc.f_qblur = 0.5;
- param->rc.f_complexity_blur = 20;
- param->rc.i_zones = 0;
-
- param->pf_log = NULL;
- param->p_log_private = NULL;
- param->i_log_level = X264_LOG_INFO;
- #if 0
-
- param->analyse.intra = X264_ANALYSE_I4x4 | X264_ANALYSE_I8x8;
- param->analyse.inter = X264_ANALYSE_I4x4 | X264_ANALYSE_I8x8
- | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16;
- #endif
- param->analyse.i_direct_mv_pred = X264_DIRECT_PRED_SPATIAL;
- param->analyse.i_me_method = X264_ME_HEX;
- param->analyse.f_psy_rd = 1.0;
- param->analyse.f_psy_trellis = 0;
- param->analyse.i_me_range = 16;
-
- #if 0
- param->analyse.i_subpel_refine = 100;
- #endif
- param->analyse.b_chroma_me = 1;
- param->analyse.i_mv_range_thread = -1;
- param->analyse.i_mv_range = -1;
- param->analyse.i_chroma_qp_offset = 0;
- param->analyse.b_fast_pskip = 1;
- param->analyse.b_dct_decimate = 1;
- param->analyse.i_luma_deadzone[0] = 21;
- param->analyse.i_luma_deadzone[1] = 11;
- param->analyse.b_psnr = 1;
- param->analyse.b_ssim = 1;
- param->i_cqm_preset = X264_CQM_FLAT;
- x264_param.rc.i_bitrate = br;
- x264_param.i_width = width;
- x264_param.i_height = height;
ffmpeg:
- c->bit_rate = 1000000;
-
- c->width = FRAMEE_WIDTH;
- c->height = FRAME_HEIGHT;
-
- c->time_base= (AVRational){1,25};
- c->gop_size = 250;
- c->max_b_frames=0;
- c->pix_fmt = PIX_FMT_YUV420P;
(孔祥文) |