diff options
| -rw-r--r-- | DOCS/man/en/mplayer.1 | 3 | ||||
| -rw-r--r-- | libmpcodecs/ve_x264.c | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1 index 7bd8da6238..72caccb199 100644 --- a/DOCS/man/en/mplayer.1 +++ b/DOCS/man/en/mplayer.1 @@ -7851,11 +7851,12 @@ Constant bitrate can be achieved by combining this with vbv_maxrate, at significant reduction in quality. . .TP -.B qp_constant=<1\-51> +.B qp_constant=<0\-51> This selects the quantizer to use for P-frames. I- and B-frames are offset from this value by ip_factor and pb_factor, respectively. 20\-40 is a useful range (default: 26). Lower values result in better fidelity, but higher bitrates. +0 is lossless. Note that quantization in H.264 works differently from MPEG-1/2/4: H.264's quantization parameter (QP) is on a logarithmic scale. The mapping is approximately H264QP = 12 + 6*log2(MPEGQP). diff --git a/libmpcodecs/ve_x264.c b/libmpcodecs/ve_x264.c index b55025083e..35c88f5653 100644 --- a/libmpcodecs/ve_x264.c +++ b/libmpcodecs/ve_x264.c @@ -107,7 +107,7 @@ static int log_level = 2; m_option_t x264encopts_conf[] = { {"bitrate", &bitrate, CONF_TYPE_INT, CONF_RANGE, 0, 24000000, NULL}, - {"qp_constant", &qp_constant, CONF_TYPE_INT, CONF_RANGE, 1, 51, NULL}, + {"qp_constant", &qp_constant, CONF_TYPE_INT, CONF_RANGE, 0, 51, NULL}, {"frameref", &frame_ref, CONF_TYPE_INT, CONF_RANGE, 1, 16, NULL}, {"keyint", &keyint_max, CONF_TYPE_INT, CONF_RANGE, 1, 24000000, NULL}, {"keyint_min", &keyint_min, CONF_TYPE_INT, CONF_RANGE, 1, 24000000, NULL}, |