| /* |
| * H.261 encoder |
| * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> |
| * Copyright (c) 2004 Maarten Daniels |
| * |
| * 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 |
| */ |
| |
| /** |
| * @file |
| * H.261 encoder. |
| */ |
| |
| #include "libavutil/attributes.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/thread.h" |
| #include "avcodec.h" |
| #include "codec_internal.h" |
| #include "mpegutils.h" |
| #include "mpegvideo.h" |
| #include "h261.h" |
| #include "h261enc.h" |
| #include "mpegvideoenc.h" |
| #include "put_bits.h" |
| |
| #define H261_MAX_RUN 26 |
| #define H261_MAX_LEVEL 15 |
| #define H261_ESC_LEN (6 + 6 + 8) |
| #define MV_TAB_OFFSET 32 |
| |
| static struct VLCLUT { |
| uint8_t len; |
| uint16_t code; |
| } vlc_lut[H261_MAX_RUN + 1][32 /* 0..2 * H261_MAX_LEN are used */]; |
| |
| // Not const despite never being initialized because doing so would |
| // put it into .rodata instead of .bss and bloat the binary. |
| // mv_penalty exists so that the motion estimation code can avoid branches. |
| static uint8_t mv_penalty[MAX_FCODE + 1][MAX_DMV * 2 + 1]; |
| static uint8_t uni_h261_rl_len [64 * 128]; |
| static uint8_t uni_h261_rl_len_last[64 * 128]; |
| static uint8_t h261_mv_codes[64][2]; |
| |
| typedef struct H261EncContext { |
| MPVMainEncContext s; |
| |
| H261Context common; |
| |
| int gob_number; |
| enum { |
| H261_QCIF = 0, |
| H261_CIF = 1, |
| } format; |
| } H261EncContext; |
| |
| static int h261_encode_picture_header(MPVMainEncContext *const m) |
| { |
| H261EncContext *const h = (H261EncContext *)m; |
| MPVEncContext *const s = &h->s.s; |
| int temp_ref; |
| |
| put_bits_assume_flushed(&s->pb); |
| |
| put_bits(&s->pb, 20, 0x10); /* PSC */ |
| |
| temp_ref = s->picture_number * 30000LL * s->c.avctx->time_base.num / |
| (1001LL * s->c.avctx->time_base.den); // FIXME maybe this should use a timestamp |
| put_sbits(&s->pb, 5, temp_ref); /* TemporalReference */ |
| |
| put_bits(&s->pb, 1, 0); /* split screen off */ |
| put_bits(&s->pb, 1, 0); /* camera off */ |
| put_bits(&s->pb, 1, s->c.pict_type == AV_PICTURE_TYPE_I); /* freeze picture release on/off */ |
| |
| put_bits(&s->pb, 1, h->format); /* 0 == QCIF, 1 == CIF */ |
| |
| put_bits(&s->pb, 1, 1); /* still image mode */ |
| put_bits(&s->pb, 1, 1); /* reserved */ |
| |
| put_bits(&s->pb, 1, 0); /* no PEI */ |
| h->gob_number = h->format - 1; |
| s->mb_skip_run = 0; |
| |
| return 0; |
| } |
| |
| /** |
| * Encode a group of blocks header. |
| */ |
| static void h261_encode_gob_header(MPVEncContext *const s, int mb_line) |
| { |
| H261EncContext *const h = (H261EncContext *)s; |
| if (h->format == H261_QCIF) { |
| h->gob_number += 2; // QCIF |
| } else { |
| h->gob_number++; // CIF |
| } |
| put_bits(&s->pb, 16, 1); /* GBSC */ |
| put_bits(&s->pb, 4, h->gob_number); /* GN */ |
| put_bits(&s->pb, 5, s->c.qscale); /* GQUANT */ |
| put_bits(&s->pb, 1, 0); /* no GEI */ |
| s->mb_skip_run = 0; |
| s->c.last_mv[0][0][0] = 0; |
| s->c.last_mv[0][0][1] = 0; |
| } |
| |
| void ff_h261_reorder_mb_index(MPVEncContext *const s) |
| { |
| const H261EncContext *const h = (H261EncContext*)s; |
| int index = s->c.mb_x + s->c.mb_y * s->c.mb_width; |
| |
| if (index % 11 == 0) { |
| if (index % 33 == 0) |
| h261_encode_gob_header(s, 0); |
| s->c.last_mv[0][0][0] = 0; |
| s->c.last_mv[0][0][1] = 0; |
| } |
| |
| /* for CIF the GOB's are fragmented in the middle of a scanline |
| * that's why we need to adjust the x and y index of the macroblocks */ |
| if (h->format == H261_CIF) { |
| s->c.mb_x = index % 11; |
| index /= 11; |
| s->c.mb_y = index % 3; |
| index /= 3; |
| s->c.mb_x += 11 * (index % 2); |
| index /= 2; |
| s->c.mb_y += 3 * index; |
| |
| ff_init_block_index(&s->c); |
| ff_update_block_index(&s->c, 8, 0, 1); |
| } |
| } |
| |
| static void h261_encode_motion(PutBitContext *pb, int val) |
| { |
| put_bits(pb, h261_mv_codes[MV_TAB_OFFSET + val][1], |
| h261_mv_codes[MV_TAB_OFFSET + val][0]); |
| } |
| |
| static inline int get_cbp(const int block_last_index[6]) |
| { |
| int i, cbp; |
| cbp = 0; |
| for (i = 0; i < 6; i++) |
| if (block_last_index[i] >= 0) |
| cbp |= 1 << (5 - i); |
| return cbp; |
| } |
| |
| /** |
| * Encode an 8x8 block. |
| * @param block the 8x8 block |
| * @param n block index (0-3 are luma, 4-5 are chroma) |
| */ |
| static void h261_encode_block(H261EncContext *h, int16_t *block, int n) |
| { |
| MPVEncContext *const s = &h->s.s; |
| int level, run, i, j, last_index, last_non_zero; |
| |
| if (s->c.mb_intra) { |
| /* DC coef */ |
| level = block[0]; |
| /* 255 cannot be represented, so we clamp */ |
| if (level > 254) { |
| level = 254; |
| block[0] = 254; |
| } |
| /* 0 cannot be represented also */ |
| else if (level < 1) { |
| level = 1; |
| block[0] = 1; |
| } |
| if (level == 128) |
| put_bits(&s->pb, 8, 0xff); |
| else |
| put_bits(&s->pb, 8, level); |
| i = 1; |
| } else if ((block[0] == 1 || block[0] == -1) && |
| (s->c.block_last_index[n] > -1)) { |
| // special case |
| put_bits(&s->pb, 2, block[0] > 0 ? 2 : 3); |
| i = 1; |
| } else { |
| i = 0; |
| } |
| |
| /* AC coefs */ |
| last_index = s->c.block_last_index[n]; |
| last_non_zero = i - 1; |
| for (; i <= last_index; i++) { |
| j = s->c.intra_scantable.permutated[i]; |
| level = block[j]; |
| if (level) { |
| run = i - last_non_zero - 1; |
| |
| if (run <= H261_MAX_RUN && |
| (unsigned)(level + H261_MAX_LEVEL) <= 2 * H261_MAX_LEVEL && |
| vlc_lut[run][level + H261_MAX_LEVEL].len) { |
| put_bits(&s->pb, vlc_lut[run][level + H261_MAX_LEVEL].len, |
| vlc_lut[run][level + H261_MAX_LEVEL].code); |
| } else { |
| /* Escape */ |
| put_bits(&s->pb, 6 + 6, (1 << 6) | run); |
| av_assert1(level != 0); |
| av_assert1(FFABS(level) <= 127); |
| put_sbits(&s->pb, 8, level); |
| } |
| last_non_zero = i; |
| } |
| } |
| if (last_index > -1) |
| put_bits(&s->pb, 2, 0x2); // EOB |
| } |
| |
| static void h261_encode_mb(MPVEncContext *const s, int16_t block[6][64], |
| int motion_x, int motion_y) |
| { |
| /* The following is only allowed because this encoder |
| * does not use slice threading. */ |
| H261EncContext *const h = (H261EncContext *)s; |
| H261Context *const com = &h->common; |
| int mvd, mv_diff_x, mv_diff_y, i, cbp; |
| cbp = 63; // avoid warning |
| mvd = 0; |
| |
| com->mtype = 0; |
| |
| if (!s->c.mb_intra) { |
| /* compute cbp */ |
| cbp = get_cbp(s->c.block_last_index); |
| |
| /* mvd indicates if this block is motion compensated */ |
| mvd = motion_x | motion_y; |
| |
| if ((cbp | mvd) == 0) { |
| /* skip macroblock */ |
| s->mb_skip_run++; |
| s->c.last_mv[0][0][0] = 0; |
| s->c.last_mv[0][0][1] = 0; |
| s->c.qscale -= s->dquant; |
| return; |
| } |
| } |
| |
| /* MB is not skipped, encode MBA */ |
| put_bits(&s->pb, |
| ff_h261_mba_bits[s->mb_skip_run], |
| ff_h261_mba_code[s->mb_skip_run]); |
| s->mb_skip_run = 0; |
| |
| /* calculate MTYPE */ |
| if (!s->c.mb_intra) { |
| com->mtype++; |
| |
| if (mvd || s->loop_filter) |
| com->mtype += 3; |
| if (s->loop_filter) |
| com->mtype += 3; |
| if (cbp) |
| com->mtype++; |
| av_assert1(com->mtype > 1); |
| } |
| |
| if (s->dquant && cbp) { |
| com->mtype++; |
| } else |
| s->c.qscale -= s->dquant; |
| |
| put_bits(&s->pb, |
| ff_h261_mtype_bits[com->mtype], |
| ff_h261_mtype_code[com->mtype]); |
| |
| com->mtype = ff_h261_mtype_map[com->mtype]; |
| |
| if (IS_QUANT(com->mtype)) { |
| ff_set_qscale(&s->c, s->c.qscale + s->dquant); |
| put_bits(&s->pb, 5, s->c.qscale); |
| } |
| |
| if (IS_16X16(com->mtype)) { |
| mv_diff_x = (motion_x >> 1) - s->c.last_mv[0][0][0]; |
| mv_diff_y = (motion_y >> 1) - s->c.last_mv[0][0][1]; |
| s->c.last_mv[0][0][0] = (motion_x >> 1); |
| s->c.last_mv[0][0][1] = (motion_y >> 1); |
| h261_encode_motion(&s->pb, mv_diff_x); |
| h261_encode_motion(&s->pb, mv_diff_y); |
| } |
| |
| if (HAS_CBP(com->mtype)) { |
| av_assert1(cbp > 0); |
| put_bits(&s->pb, |
| ff_h261_cbp_tab[cbp - 1][1], |
| ff_h261_cbp_tab[cbp - 1][0]); |
| } |
| for (i = 0; i < 6; i++) |
| /* encode each block */ |
| h261_encode_block(h, block[i], i); |
| |
| if (!IS_16X16(com->mtype)) { |
| s->c.last_mv[0][0][0] = 0; |
| s->c.last_mv[0][0][1] = 0; |
| } |
| } |
| |
| static av_cold void h261_encode_init_static(void) |
| { |
| uint8_t (*const mv_codes)[2] = h261_mv_codes + MV_TAB_OFFSET; |
| memset(uni_h261_rl_len, H261_ESC_LEN, sizeof(uni_h261_rl_len)); |
| memset(uni_h261_rl_len_last, H261_ESC_LEN + 2 /* EOB */, sizeof(uni_h261_rl_len_last)); |
| |
| // The following loop is over the ordinary elements, not EOB or escape. |
| for (size_t i = 1; i < FF_ARRAY_ELEMS(ff_h261_tcoeff_vlc) - 1; i++) { |
| unsigned run = ff_h261_tcoeff_run[i]; |
| unsigned level = ff_h261_tcoeff_level[i]; |
| unsigned len = ff_h261_tcoeff_vlc[i][1] + 1 /* sign */; |
| unsigned code = ff_h261_tcoeff_vlc[i][0]; |
| |
| vlc_lut[run][H261_MAX_LEVEL + level] = (struct VLCLUT){ len, code << 1 }; |
| vlc_lut[run][H261_MAX_LEVEL - level] = (struct VLCLUT){ len, (code << 1) | 1 }; |
| |
| uni_h261_rl_len [UNI_AC_ENC_INDEX(run, 64 + level)] = len; |
| uni_h261_rl_len [UNI_AC_ENC_INDEX(run, 64 - level)] = len; |
| uni_h261_rl_len_last[UNI_AC_ENC_INDEX(run, 64 + level)] = len + 2; |
| uni_h261_rl_len_last[UNI_AC_ENC_INDEX(run, 64 - level)] = len + 2; |
| } |
| |
| for (ptrdiff_t i = 1;; i++) { |
| // sign-one MV codes; diff -16..-1, 16..31 |
| mv_codes[32 - i][0] = mv_codes[-i][0] = (ff_h261_mv_tab[i][0] << 1) | 1 /* sign */; |
| mv_codes[32 - i][1] = mv_codes[-i][1] = ff_h261_mv_tab[i][1] + 1; |
| if (i == 16) |
| break; |
| // sign-zero MV codes: diff -31..-17, 1..15 |
| mv_codes[i][0] = mv_codes[i - 32][0] = ff_h261_mv_tab[i][0] << 1; |
| mv_codes[i][1] = mv_codes[i - 32][1] = ff_h261_mv_tab[i][1] + 1; |
| } |
| // MV code for difference zero; has no sign |
| mv_codes[0][0] = 1; |
| mv_codes[0][1] = 1; |
| } |
| |
| static av_cold int h261_encode_init(AVCodecContext *avctx) |
| { |
| static AVOnce init_static_once = AV_ONCE_INIT; |
| H261EncContext *const h = avctx->priv_data; |
| MPVEncContext *const s = &h->s.s; |
| |
| if (avctx->width == 176 && avctx->height == 144) { |
| h->format = H261_QCIF; |
| } else if (avctx->width == 352 && avctx->height == 288) { |
| h->format = H261_CIF; |
| } else { |
| av_log(avctx, AV_LOG_ERROR, |
| "The specified picture size of %dx%d is not valid for the " |
| "H.261 codec.\nValid sizes are 176x144, 352x288\n", |
| avctx->width, avctx->height); |
| return AVERROR(EINVAL); |
| } |
| s->c.private_ctx = &h->common; |
| h->s.encode_picture_header = h261_encode_picture_header; |
| s->encode_mb = h261_encode_mb; |
| |
| s->min_qcoeff = -127; |
| s->max_qcoeff = 127; |
| s->ac_esc_length = H261_ESC_LEN; |
| |
| s->me.mv_penalty = mv_penalty; |
| |
| s->intra_ac_vlc_length = s->inter_ac_vlc_length = uni_h261_rl_len; |
| s->intra_ac_vlc_last_length = s->inter_ac_vlc_last_length = uni_h261_rl_len_last; |
| ff_thread_once(&init_static_once, h261_encode_init_static); |
| |
| return ff_mpv_encode_init(avctx); |
| } |
| |
| const FFCodec ff_h261_encoder = { |
| .p.name = "h261", |
| CODEC_LONG_NAME("H.261"), |
| .p.type = AVMEDIA_TYPE_VIDEO, |
| .p.id = AV_CODEC_ID_H261, |
| .p.priv_class = &ff_mpv_enc_class, |
| .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE, |
| .priv_data_size = sizeof(H261EncContext), |
| .init = h261_encode_init, |
| FF_CODEC_ENCODE_CB(ff_mpv_encode_picture), |
| .close = ff_mpv_encode_end, |
| .caps_internal = FF_CODEC_CAP_INIT_CLEANUP, |
| CODEC_PIXFMTS(AV_PIX_FMT_YUV420P), |
| .color_ranges = AVCOL_RANGE_MPEG, |
| }; |
