X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Favc.c;h=a041e843574845e29a125d99861fcf5b33ac26a4;hb=24a64e0462d5dad6f6cf629243abdbe975e33015;hp=ec50033a0420ea7402c3eb9b0dbbd26c740ee568;hpb=ace96d2e693d804a0ed16aebc1b1027cfff2c527;p=ffmpeg diff --git a/libavformat/avc.c b/libavformat/avc.c index ec50033a042..a041e843574 100644 --- a/libavformat/avc.c +++ b/libavformat/avc.c @@ -21,6 +21,7 @@ #include "libavutil/intreadwrite.h" #include "libavcodec/h264.h" +#include "libavcodec/get_bits.h" #include "avformat.h" #include "avio.h" #include "avc.h" @@ -241,3 +242,188 @@ const uint8_t *ff_avc_mp4_find_startcode(const uint8_t *start, return start + res; } + +uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len, + uint32_t *dst_len, int header_len) +{ + uint8_t *dst; + uint32_t i, len; + + dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE); + if (!dst) + return NULL; + + /* NAL unit header */ + i = len = 0; + while (i < header_len && i < src_len) + dst[len++] = src[i++]; + + while (i + 2 < src_len) + if (!src[i] && !src[i + 1] && src[i + 2] == 3) { + dst[len++] = src[i++]; + dst[len++] = src[i++]; + i++; // remove emulation_prevention_three_byte + } else + dst[len++] = src[i++]; + + while (i < src_len) + dst[len++] = src[i++]; + + memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE); + + *dst_len = len; + return dst; +} + +static const AVRational avc_sample_aspect_ratio[17] = { + { 0, 1 }, + { 1, 1 }, + { 12, 11 }, + { 10, 11 }, + { 16, 11 }, + { 40, 33 }, + { 24, 11 }, + { 20, 11 }, + { 32, 11 }, + { 80, 33 }, + { 18, 11 }, + { 15, 11 }, + { 64, 33 }, + { 160, 99 }, + { 4, 3 }, + { 3, 2 }, + { 2, 1 }, +}; + +static inline int get_ue_golomb(GetBitContext *gb) { + int i; + for (i = 0; i < 32 && !get_bits1(gb); i++) + ; + return get_bitsz(gb, i) + (1 << i) - 1; +} + +static inline int get_se_golomb(GetBitContext *gb) { + int v = get_ue_golomb(gb) + 1; + int sign = -(v & 1); + return ((v >> 1) ^ sign) - sign; +} + +H264SequenceParameterSet *ff_avc_decode_sps(const uint8_t *buf, int buf_size) +{ + int i, j, ret, rbsp_size, aspect_ratio_idc, pic_order_cnt_type; + int num_ref_frames_in_pic_order_cnt_cycle; + int delta_scale, lastScale = 8, nextScale = 8; + int sizeOfScalingList; + H264SequenceParameterSet *sps = NULL; + GetBitContext gb; + uint8_t *rbsp_buf; + + rbsp_buf = ff_nal_unit_extract_rbsp(buf, buf_size, &rbsp_size, 0); + if (!rbsp_buf) + return NULL; + + ret = init_get_bits8(&gb, rbsp_buf, rbsp_size); + if (ret < 0) + goto end; + + sps = av_mallocz(sizeof(*sps)); + if (!sps) + goto end; + + sps->profile_idc = get_bits(&gb, 8); + sps->constraint_set_flags |= get_bits1(&gb) << 0; // constraint_set0_flag + sps->constraint_set_flags |= get_bits1(&gb) << 1; // constraint_set1_flag + sps->constraint_set_flags |= get_bits1(&gb) << 2; // constraint_set2_flag + sps->constraint_set_flags |= get_bits1(&gb) << 3; // constraint_set3_flag + sps->constraint_set_flags |= get_bits1(&gb) << 4; // constraint_set4_flag + sps->constraint_set_flags |= get_bits1(&gb) << 5; // constraint_set5_flag + skip_bits(&gb, 2); // reserved_zero_2bits + sps->level_idc = get_bits(&gb, 8); + sps->id = get_ue_golomb(&gb); + + if (sps->profile_idc == 100 || sps->profile_idc == 110 || + sps->profile_idc == 122 || sps->profile_idc == 244 || sps->profile_idc == 44 || + sps->profile_idc == 83 || sps->profile_idc == 86 || sps->profile_idc == 118 || + sps->profile_idc == 128 || sps->profile_idc == 138 || sps->profile_idc == 139 || + sps->profile_idc == 134) { + sps->chroma_format_idc = get_ue_golomb(&gb); // chroma_format_idc + if (sps->chroma_format_idc == 3) { + skip_bits1(&gb); // separate_colour_plane_flag + } + sps->bit_depth_luma = get_ue_golomb(&gb) + 8; + get_ue_golomb(&gb); // bit_depth_chroma_minus8 + skip_bits1(&gb); // qpprime_y_zero_transform_bypass_flag + if (get_bits1(&gb)) { // seq_scaling_matrix_present_flag + for (i = 0; i < ((sps->chroma_format_idc != 3) ? 8 : 12); i++) { + if (!get_bits1(&gb)) // seq_scaling_list_present_flag + continue; + lastScale = 8; + nextScale = 8; + sizeOfScalingList = i < 6 ? 16 : 64; + for (j = 0; j < sizeOfScalingList; j++) { + if (nextScale != 0) { + delta_scale = get_se_golomb(&gb); + nextScale = (lastScale + delta_scale) & 0xff; + } + lastScale = nextScale == 0 ? lastScale : nextScale; + } + } + } + } else { + sps->chroma_format_idc = 1; + sps->bit_depth_luma = 8; + } + + get_ue_golomb(&gb); // log2_max_frame_num_minus4 + pic_order_cnt_type = get_ue_golomb(&gb); + + if (pic_order_cnt_type == 0) { + get_ue_golomb(&gb); // log2_max_pic_order_cnt_lsb_minus4 + } else if (pic_order_cnt_type == 1) { + skip_bits1(&gb); // delta_pic_order_always_zero + get_se_golomb(&gb); // offset_for_non_ref_pic + get_se_golomb(&gb); // offset_for_top_to_bottom_field + num_ref_frames_in_pic_order_cnt_cycle = get_ue_golomb(&gb); + for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) + get_se_golomb(&gb); // offset_for_ref_frame + } + + get_ue_golomb(&gb); // max_num_ref_frames + skip_bits1(&gb); // gaps_in_frame_num_value_allowed_flag + get_ue_golomb(&gb); // pic_width_in_mbs_minus1 + get_ue_golomb(&gb); // pic_height_in_map_units_minus1 + + sps->frame_mbs_only_flag = get_bits1(&gb); + if (!sps->frame_mbs_only_flag) + skip_bits1(&gb); // mb_adaptive_frame_field_flag + + skip_bits1(&gb); // direct_8x8_inference_flag + + if (get_bits1(&gb)) { // frame_cropping_flag + get_ue_golomb(&gb); // frame_crop_left_offset + get_ue_golomb(&gb); // frame_crop_right_offset + get_ue_golomb(&gb); // frame_crop_top_offset + get_ue_golomb(&gb); // frame_crop_bottom_offset + } + + if (get_bits1(&gb)) { // vui_parameters_present_flag + if (get_bits1(&gb)) { // aspect_ratio_info_present_flag + aspect_ratio_idc = get_bits(&gb, 8); + if (aspect_ratio_idc == 0xff) { + sps->sar.num = get_bits(&gb, 16); + sps->sar.den = get_bits(&gb, 16); + } else if (aspect_ratio_idc < FF_ARRAY_ELEMS(avc_sample_aspect_ratio)) { + sps->sar = avc_sample_aspect_ratio[aspect_ratio_idc]; + } + } + } + + if (!sps->sar.den) { + sps->sar.num = 1; + sps->sar.den = 1; + } + + end: + av_free(rbsp_buf); + return sps; +}