ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinha...@outlook.com> | Sun Jun 15 23:12:14 2025 +0200| [b38f23663e7648b34857450060dbf3af562a00d4] | committer: Andreas Rheinhardt
avcodec/mpeg12dec: Put GetBitContext on the stack where advantageous This is in preparation for no longer using MpegEncContext.gb. Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b38f23663e7648b34857450060dbf3af562a00d4 --- libavcodec/mpeg12dec.c | 192 ++++++++++++++++++++++++++----------------------- 1 file changed, 102 insertions(+), 90 deletions(-) diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c index 5d2719d0f0..ec8b213206 100644 --- a/libavcodec/mpeg12dec.c +++ b/libavcodec/mpeg12dec.c @@ -44,6 +44,7 @@ #include "codec_internal.h" #include "decode.h" #include "error_resilience.h" +#include "get_bits.h" #include "hwaccel_internal.h" #include "hwconfig.h" #include "idctdsp.h" @@ -969,23 +970,24 @@ static int mpeg1_decode_picture(AVCodecContext *avctx, const uint8_t *buf, { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; + GetBitContext gb0, *const gb = &gb0; int ref, f_code, vbv_delay, ret; - ret = init_get_bits8(&s->gb, buf, buf_size); + ret = init_get_bits8(gb, buf, buf_size); if (ret < 0) return ret; - ref = get_bits(&s->gb, 10); /* temporal ref */ - s->pict_type = get_bits(&s->gb, 3); + ref = get_bits(gb, 10); /* temporal ref */ + s->pict_type = get_bits(gb, 3); if (s->pict_type == 0 || s->pict_type > 3) return AVERROR_INVALIDDATA; - vbv_delay = get_bits(&s->gb, 16); + vbv_delay = get_bits(gb, 16); s1->vbv_delay = vbv_delay; if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type == AV_PICTURE_TYPE_B) { - s->full_pel[0] = get_bits1(&s->gb); - f_code = get_bits(&s->gb, 3); + s->full_pel[0] = get_bits1(gb); + f_code = get_bits(gb, 3); if (f_code == 0 && (avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))) return AVERROR_INVALIDDATA; f_code += !f_code; @@ -993,8 +995,8 @@ static int mpeg1_decode_picture(AVCodecContext *avctx, const uint8_t *buf, s->mpeg_f_code[0][1] = f_code; } if (s->pict_type == AV_PICTURE_TYPE_B) { - s->full_pel[1] = get_bits1(&s->gb); - f_code = get_bits(&s->gb, 3); + s->full_pel[1] = get_bits1(gb); + f_code = get_bits(gb, 3); if (f_code == 0 && (avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))) return AVERROR_INVALIDDATA; f_code += !f_code; @@ -1009,38 +1011,39 @@ static int mpeg1_decode_picture(AVCodecContext *avctx, const uint8_t *buf, return 0; } -static void mpeg_decode_sequence_extension(Mpeg1Context *s1) +static void mpeg_decode_sequence_extension(Mpeg1Context *const s1, + GetBitContext *const gb) { MpegEncContext *s = &s1->mpeg_enc_ctx; int horiz_size_ext, vert_size_ext; int bit_rate_ext; - skip_bits(&s->gb, 1); /* profile and level esc*/ - s->avctx->profile = get_bits(&s->gb, 3); - s->avctx->level = get_bits(&s->gb, 4); - s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */ - s->chroma_format = get_bits(&s->gb, 2); /* chroma_format 1=420, 2=422, 3=444 */ + skip_bits(gb, 1); /* profile and level esc*/ + s->avctx->profile = get_bits(gb, 3); + s->avctx->level = get_bits(gb, 4); + s->progressive_sequence = get_bits1(gb); /* progressive_sequence */ + s->chroma_format = get_bits(gb, 2); /* chroma_format 1=420, 2=422, 3=444 */ if (!s->chroma_format) { s->chroma_format = CHROMA_420; av_log(s->avctx, AV_LOG_WARNING, "Chroma format invalid\n"); } - horiz_size_ext = get_bits(&s->gb, 2); - vert_size_ext = get_bits(&s->gb, 2); + horiz_size_ext = get_bits(gb, 2); + vert_size_ext = get_bits(gb, 2); s->width |= (horiz_size_ext << 12); s->height |= (vert_size_ext << 12); - bit_rate_ext = get_bits(&s->gb, 12); /* XXX: handle it */ + bit_rate_ext = get_bits(gb, 12); /* XXX: handle it */ s1->bit_rate += (bit_rate_ext << 18) * 400LL; - check_marker(s->avctx, &s->gb, "after bit rate extension"); - s->avctx->rc_buffer_size += get_bits(&s->gb, 8) * 1024 * 16 << 10; + check_marker(s->avctx, gb, "after bit rate extension"); + s->avctx->rc_buffer_size += get_bits(gb, 8) * 1024 * 16 << 10; - s->low_delay = get_bits1(&s->gb); + s->low_delay = get_bits1(gb); if (s->avctx->flags & AV_CODEC_FLAG_LOW_DELAY) s->low_delay = 1; - s1->frame_rate_ext.num = get_bits(&s->gb, 2) + 1; - s1->frame_rate_ext.den = get_bits(&s->gb, 5) + 1; + s1->frame_rate_ext.num = get_bits(gb, 2) + 1; + s1->frame_rate_ext.den = get_bits(gb, 5) + 1; ff_dlog(s->avctx, "sequence extension\n"); s->codec_id = s->avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO; @@ -1052,21 +1055,22 @@ static void mpeg_decode_sequence_extension(Mpeg1Context *s1) s->avctx->rc_buffer_size, s1->bit_rate); } -static void mpeg_decode_sequence_display_extension(Mpeg1Context *s1) +static void mpeg_decode_sequence_display_extension(Mpeg1Context *const s1, + GetBitContext *const gb) { MpegEncContext *s = &s1->mpeg_enc_ctx; int color_description, w, h; - skip_bits(&s->gb, 3); /* video format */ - color_description = get_bits1(&s->gb); + skip_bits(gb, 3); /* video format */ + color_description = get_bits1(gb); if (color_description) { - s->avctx->color_primaries = get_bits(&s->gb, 8); - s->avctx->color_trc = get_bits(&s->gb, 8); - s->avctx->colorspace = get_bits(&s->gb, 8); + s->avctx->color_primaries = get_bits(gb, 8); + s->avctx->color_trc = get_bits(gb, 8); + s->avctx->colorspace = get_bits(gb, 8); } - w = get_bits(&s->gb, 14); - skip_bits(&s->gb, 1); // marker - h = get_bits(&s->gb, 14); + w = get_bits(gb, 14); + skip_bits(gb, 1); // marker + h = get_bits(gb, 14); // remaining 3 bits are zero padding s1->pan_scan.width = 16 * w; @@ -1076,7 +1080,8 @@ static void mpeg_decode_sequence_display_extension(Mpeg1Context *s1) av_log(s->avctx, AV_LOG_DEBUG, "sde w:%d, h:%d\n", w, h); } -static void mpeg_decode_picture_display_extension(Mpeg1Context *s1) +static void mpeg_decode_picture_display_extension(Mpeg1Context *const s1, + GetBitContext *const gb) { MpegEncContext *s = &s1->mpeg_enc_ctx; int i, nofco; @@ -1096,10 +1101,10 @@ static void mpeg_decode_picture_display_extension(Mpeg1Context *s1) } } for (i = 0; i < nofco; i++) { - s1->pan_scan.position[i][0] = get_sbits(&s->gb, 16); - skip_bits(&s->gb, 1); // marker - s1->pan_scan.position[i][1] = get_sbits(&s->gb, 16); - skip_bits(&s->gb, 1); // marker + s1->pan_scan.position[i][0] = get_sbits(gb, 16); + skip_bits(gb, 1); // marker + s1->pan_scan.position[i][1] = get_sbits(gb, 16); + skip_bits(gb, 1); // marker } if (s->avctx->debug & FF_DEBUG_PICT_INFO) @@ -1110,14 +1115,14 @@ static void mpeg_decode_picture_display_extension(Mpeg1Context *s1) s1->pan_scan.position[2][0], s1->pan_scan.position[2][1]); } -static int load_matrix(MpegEncContext *s, uint16_t matrix0[64], - uint16_t matrix1[64], int intra) +static int load_matrix(MPVContext *const s, GetBitContext *const gb, + uint16_t matrix0[64], uint16_t matrix1[64], int intra) { int i; for (i = 0; i < 64; i++) { int j = s->idsp.idct_permutation[ff_zigzag_direct[i]]; - int v = get_bits(&s->gb, 8); + int v = get_bits(gb, 8); if (v == 0) { av_log(s->avctx, AV_LOG_ERROR, "matrix damaged\n"); return AVERROR_INVALIDDATA; @@ -1133,29 +1138,31 @@ static int load_matrix(MpegEncContext *s, uint16_t matrix0[64], return 0; } -static void mpeg_decode_quant_matrix_extension(MpegEncContext *s) +static void mpeg_decode_quant_matrix_extension(MPVContext *const s, + GetBitContext *const gb) { ff_dlog(s->avctx, "matrix extension\n"); - if (get_bits1(&s->gb)) - load_matrix(s, s->chroma_intra_matrix, s->intra_matrix, 1); - if (get_bits1(&s->gb)) - load_matrix(s, s->chroma_inter_matrix, s->inter_matrix, 0); - if (get_bits1(&s->gb)) - load_matrix(s, s->chroma_intra_matrix, NULL, 1); - if (get_bits1(&s->gb)) - load_matrix(s, s->chroma_inter_matrix, NULL, 0); + if (get_bits1(gb)) + load_matrix(s, gb, s->chroma_intra_matrix, s->intra_matrix, 1); + if (get_bits1(gb)) + load_matrix(s, gb, s->chroma_inter_matrix, s->inter_matrix, 0); + if (get_bits1(gb)) + load_matrix(s, gb, s->chroma_intra_matrix, NULL, 1); + if (get_bits1(gb)) + load_matrix(s, gb, s->chroma_inter_matrix, NULL, 0); } -static int mpeg_decode_picture_coding_extension(Mpeg1Context *s1) +static int mpeg_decode_picture_coding_extension(Mpeg1Context *const s1, + GetBitContext *const gb) { MpegEncContext *s = &s1->mpeg_enc_ctx; s->full_pel[0] = s->full_pel[1] = 0; - s->mpeg_f_code[0][0] = get_bits(&s->gb, 4); - s->mpeg_f_code[0][1] = get_bits(&s->gb, 4); - s->mpeg_f_code[1][0] = get_bits(&s->gb, 4); - s->mpeg_f_code[1][1] = get_bits(&s->gb, 4); + s->mpeg_f_code[0][0] = get_bits(gb, 4); + s->mpeg_f_code[0][1] = get_bits(gb, 4); + s->mpeg_f_code[1][0] = get_bits(gb, 4); + s->mpeg_f_code[1][1] = get_bits(gb, 4); s->mpeg_f_code[0][0] += !s->mpeg_f_code[0][0]; s->mpeg_f_code[0][1] += !s->mpeg_f_code[0][1]; s->mpeg_f_code[1][0] += !s->mpeg_f_code[1][0]; @@ -1174,17 +1181,17 @@ static int mpeg_decode_picture_coding_extension(Mpeg1Context *s1) s->pict_type = AV_PICTURE_TYPE_B; } - s->intra_dc_precision = get_bits(&s->gb, 2); - s->picture_structure = get_bits(&s->gb, 2); - s->top_field_first = get_bits1(&s->gb); - s->frame_pred_frame_dct = get_bits1(&s->gb); - s->concealment_motion_vectors = get_bits1(&s->gb); - s->q_scale_type = get_bits1(&s->gb); - s->intra_vlc_format = get_bits1(&s->gb); - s->alternate_scan = get_bits1(&s->gb); - s->repeat_first_field = get_bits1(&s->gb); - s->chroma_420_type = get_bits1(&s->gb); - s->progressive_frame = get_bits1(&s->gb); + s->intra_dc_precision = get_bits(gb, 2); + s->picture_structure = get_bits(gb, 2); + s->top_field_first = get_bits1(gb); + s->frame_pred_frame_dct = get_bits1(gb); + s->concealment_motion_vectors = get_bits1(gb); + s->q_scale_type = get_bits1(gb); + s->intra_vlc_format = get_bits1(gb); + s->alternate_scan = get_bits1(gb); + s->repeat_first_field = get_bits1(gb); + s->chroma_420_type = get_bits1(gb); + s->progressive_frame = get_bits1(gb); // We only initialize intra_scantable.permutated, as this is all we use. ff_permute_scantable(s->intra_scantable.permutated, @@ -1724,44 +1731,45 @@ static int mpeg1_decode_sequence(AVCodecContext *avctx, { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; + GetBitContext gb0, *const gb = &gb0; int width, height; int i, v, j; - int ret = init_get_bits8(&s->gb, buf, buf_size); + int ret = init_get_bits8(gb, buf, buf_size); if (ret < 0) return ret; - width = get_bits(&s->gb, 12); - height = get_bits(&s->gb, 12); + width = get_bits(gb, 12); + height = get_bits(gb, 12); if (width == 0 || height == 0) { av_log(avctx, AV_LOG_WARNING, "Invalid horizontal or vertical size value.\n"); if (avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_COMPLIANT)) return AVERROR_INVALIDDATA; } - s1->aspect_ratio_info = get_bits(&s->gb, 4); + s1->aspect_ratio_info = get_bits(gb, 4); if (s1->aspect_ratio_info == 0) { av_log(avctx, AV_LOG_ERROR, "aspect ratio has forbidden 0 value\n"); if (avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_COMPLIANT)) return AVERROR_INVALIDDATA; } - s1->frame_rate_index = get_bits(&s->gb, 4); + s1->frame_rate_index = get_bits(gb, 4); if (s1->frame_rate_index == 0 || s1->frame_rate_index > 13) { av_log(avctx, AV_LOG_WARNING, "frame_rate_index %d is invalid\n", s1->frame_rate_index); s1->frame_rate_index = 1; } - s1->bit_rate = get_bits(&s->gb, 18) * 400; - if (check_marker(s->avctx, &s->gb, "in sequence header") == 0) { + s1->bit_rate = get_bits(gb, 18) * 400; + if (check_marker(s->avctx, gb, "in sequence header") == 0) { return AVERROR_INVALIDDATA; } - s->avctx->rc_buffer_size = get_bits(&s->gb, 10) * 1024 * 16; - skip_bits(&s->gb, 1); + s->avctx->rc_buffer_size = get_bits(gb, 10) * 1024 * 16; + skip_bits(gb, 1); /* get matrix */ - if (get_bits1(&s->gb)) { - load_matrix(s, s->chroma_intra_matrix, s->intra_matrix, 1); + if (get_bits1(gb)) { + load_matrix(s, gb, s->chroma_intra_matrix, s->intra_matrix, 1); } else { for (i = 0; i < 64; i++) { j = s->idsp.idct_permutation[i]; @@ -1770,8 +1778,8 @@ static int mpeg1_decode_sequence(AVCodecContext *avctx, s->chroma_intra_matrix[j] = v; } } - if (get_bits1(&s->gb)) { - load_matrix(s, s->chroma_inter_matrix, s->inter_matrix, 0); + if (get_bits1(gb)) { + load_matrix(s, gb, s->chroma_inter_matrix, s->inter_matrix, 0); } else { for (i = 0; i < 64; i++) { int j = s->idsp.idct_permutation[i]; @@ -1781,7 +1789,7 @@ static int mpeg1_decode_sequence(AVCodecContext *avctx, } } - if (show_bits(&s->gb, 23) != 0) { + if (show_bits(gb, 23) != 0) { av_log(s->avctx, AV_LOG_ERROR, "sequence header damaged\n"); return AVERROR_INVALIDDATA; } @@ -2158,20 +2166,21 @@ static int mpeg_decode_gop(AVCodecContext *avctx, { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; + GetBitContext gb0, *const gb = &gb0; int broken_link; int64_t tc; - int ret = init_get_bits8(&s->gb, buf, buf_size); + int ret = init_get_bits8(gb, buf, buf_size); if (ret < 0) return ret; - tc = s1->timecode_frame_start = get_bits(&s->gb, 25); + tc = s1->timecode_frame_start = get_bits(gb, 25); - s1->closed_gop = get_bits1(&s->gb); + s1->closed_gop = get_bits1(gb); /* broken_link indicates that after editing the * reference frames of the first B-Frames after GOP I-Frame * are missing (open gop) */ - broken_link = get_bits1(&s->gb); + broken_link = get_bits1(gb); if (s->avctx->debug & FF_DEBUG_PICT_INFO) { char tcbuf[AV_TIMECODE_STR_SIZE]; @@ -2313,15 +2322,17 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture, return AVERROR_INVALIDDATA; } break; - case EXT_START_CODE: - ret = init_get_bits8(&s2->gb, buf_ptr, input_size); + case EXT_START_CODE: { + GetBitContext gb0, *const gb = &gb0; + + ret = init_get_bits8(gb, buf_ptr, input_size); if (ret < 0) return ret; - switch (get_bits(&s2->gb, 4)) { + switch (get_bits(gb, 4)) { case 0x1: if (last_code == 0) { - mpeg_decode_sequence_extension(s); + mpeg_decode_sequence_extension(s, gb); } else { av_log(avctx, AV_LOG_ERROR, "ignoring seq ext after %X\n", last_code); @@ -2330,17 +2341,17 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture, } break; case 0x2: - mpeg_decode_sequence_display_extension(s); + mpeg_decode_sequence_display_extension(s, gb); break; case 0x3: - mpeg_decode_quant_matrix_extension(s2); + mpeg_decode_quant_matrix_extension(s2, gb); break; case 0x7: - mpeg_decode_picture_display_extension(s); + mpeg_decode_picture_display_extension(s, gb); break; case 0x8: if (last_code == PICTURE_START_CODE) { - int ret = mpeg_decode_picture_coding_extension(s); + int ret = mpeg_decode_picture_coding_extension(s, gb); if (ret < 0) return ret; } else { @@ -2352,6 +2363,7 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture, break; } break; + } case USER_START_CODE: mpeg_decode_user_data(avctx, buf_ptr, input_size); break; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
