From cc549149d3bcb653976193eb56aedb3589e7347e Mon Sep 17 00:00:00 2001 From: Mark Thompson Date: Tue, 18 Sep 2018 23:30:57 +0100 Subject: lavc/h264: Add common code for level handling Including a unit test. --- libavcodec/h264_levels.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 libavcodec/h264_levels.c (limited to 'libavcodec/h264_levels.c') diff --git a/libavcodec/h264_levels.c b/libavcodec/h264_levels.c new file mode 100644 index 0000000000..6b4e18a914 --- /dev/null +++ b/libavcodec/h264_levels.c @@ -0,0 +1,130 @@ +/* + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "avcodec.h" +#include "h264_levels.h" + +// H.264 table A-1. +static const H264LevelDescriptor h264_levels[] = { + // Name MaxMBPS MaxBR MinCR + // | level_idc | MaxFS | MaxCPB | MaxMvsPer2Mb + // | | cs3f | | MaxDpbMbs | | MaxVmvR | | + { "1", 10, 0, 1485, 99, 396, 64, 175, 64, 2, 0 }, + { "1b", 10, 1, 1485, 99, 396, 128, 350, 64, 2, 0 }, + { "1b", 9, 0, 1485, 99, 396, 128, 350, 64, 2, 0 }, + { "1.1", 11, 0, 3000, 396, 900, 192, 500, 128, 2, 0 }, + { "1.2", 12, 0, 6000, 396, 2376, 384, 1000, 128, 2, 0 }, + { "1.3", 13, 0, 11880, 396, 2376, 768, 2000, 128, 2, 0 }, + { "2", 20, 0, 11880, 396, 2376, 2000, 2000, 128, 2, 0 }, + { "2.1", 21, 0, 19800, 792, 4752, 4000, 4000, 256, 2, 0 }, + { "2.2", 22, 0, 20250, 1620, 8100, 4000, 4000, 256, 2, 0 }, + { "3", 30, 0, 40500, 1620, 8100, 10000, 10000, 256, 2, 32 }, + { "3.1", 31, 0, 108000, 3600, 18000, 14000, 14000, 512, 4, 16 }, + { "3.2", 32, 0, 216000, 5120, 20480, 20000, 20000, 512, 4, 16 }, + { "4", 40, 0, 245760, 8192, 32768, 20000, 25000, 512, 4, 16 }, + { "4.1", 41, 0, 245760, 8192, 32768, 50000, 62500, 512, 2, 16 }, + { "4.2", 42, 0, 522240, 8704, 34816, 50000, 62500, 512, 2, 16 }, + { "5", 50, 0, 589824, 22080, 110400, 135000, 135000, 512, 2, 16 }, + { "5.1", 51, 0, 983040, 36864, 184320, 240000, 240000, 512, 2, 16 }, + { "5.2", 52, 0, 2073600, 36864, 184320, 240000, 240000, 512, 2, 16 }, + { "6", 60, 0, 4177920, 139264, 696320, 240000, 240000, 8192, 2, 16 }, + { "6.1", 61, 0, 8355840, 139264, 696320, 480000, 480000, 8192, 2, 16 }, + { "6.2", 62, 0, 16711680, 139264, 696320, 800000, 800000, 8192, 2, 16 }, +}; + +// H.264 table A-2 plus values from A-1. +static const struct { + int profile_idc; + int cpb_br_vcl_factor; + int cpb_br_nal_factor; +} h264_br_factors[] = { + { 66, 1000, 1200 }, + { 77, 1000, 1200 }, + { 88, 1000, 1200 }, + { 100, 1250, 1500 }, + { 110, 3000, 3600 }, + { 122, 4000, 4800 }, + { 244, 4000, 4800 }, + { 44, 4000, 4800 }, +}; + +// We are only ever interested in the NAL bitrate factor. +static int h264_get_br_factor(int profile_idc) +{ + int i; + for (i = 0; i < FF_ARRAY_ELEMS(h264_br_factors); i++) { + if (h264_br_factors[i].profile_idc == profile_idc) + return h264_br_factors[i].cpb_br_nal_factor; + } + // Default to the non-high profile value if not specified. + return 1200; +} + +const H264LevelDescriptor *ff_h264_get_level(int level_idc, + int constraint_set3_flag) +{ + int i; + for (i = 0; i < FF_ARRAY_ELEMS(h264_levels); i++) { + if (h264_levels[i].level_idc == level_idc && + h264_levels[i].constraint_set3_flag == constraint_set3_flag) + return &h264_levels[i]; + } + return NULL; +} + +const H264LevelDescriptor *ff_h264_guess_level(int profile_idc, + int64_t bitrate, + int width, int height, + int max_dec_frame_buffering) +{ + int width_mbs = (width + 15) / 16; + int height_mbs = (height + 15) / 16; + int no_cs3f = !(profile_idc == 66 || + profile_idc == 77 || + profile_idc == 88); + int i; + + for (i = 0; i < FF_ARRAY_ELEMS(h264_levels); i++) { + const H264LevelDescriptor *level = &h264_levels[i]; + + if (level->constraint_set3_flag && no_cs3f) + continue; + + if (bitrate > level->max_br * h264_get_br_factor(profile_idc)) + continue; + + if (width_mbs * height_mbs > level->max_fs) + continue; + if (width_mbs * width_mbs > 8 * level->max_fs) + continue; + if (height_mbs * height_mbs > 8 * level->max_fs) + continue; + + if (width_mbs && height_mbs) { + int max_dpb_frames = + FFMIN(level->max_dpb_mbs / (width_mbs * height_mbs), 16); + if (max_dec_frame_buffering > max_dpb_frames) + continue; + } + + return level; + } + + // No usable levels found - frame is too big or bitrate is too high. + return NULL; +} -- cgit v1.2.1