/* * RV10/RV20 decoder * Copyright (c) 2000,2001 Fabrice Bellard * Copyright (c) 2002-2004 Michael Niedermayer * * 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 * RV10/RV20 decoder */ #include #include "libavutil/imgutils.h" #include "libavutil/thread.h" #include "avcodec.h" #include "codec_internal.h" #include "decode.h" #include "error_resilience.h" #include "h263.h" #include "h263data.h" #include "h263dec.h" #include "mpeg_er.h" #include "mpegutils.h" #include "mpegvideo.h" #include "mpegvideodec.h" #include "mpeg4video.h" #include "mpegvideodata.h" #include "rv10dec.h" #define RV_GET_MAJOR_VER(x) ((x) >> 28) #define RV_GET_MINOR_VER(x) (((x) >> 20) & 0xFF) #define RV_GET_MICRO_VER(x) (((x) >> 12) & 0xFF) #define MAX_VLC_ENTRIES 1023 // Note: Does not include the skip entries. #define DC_VLC_BITS 9 typedef struct RVDecContext { MpegEncContext m; int sub_id; int orig_width, orig_height; } RVDecContext; /* (run, length) encoded value for the symbols table. The actual symbols * are run..run - length (mod 256). * The last two entries in the following table apply to luma only. * The skip values are not included in this list. */ static const uint8_t rv_sym_run_len[][2] = { { 0, 0 }, { 1, 0 }, { 255, 0 }, { 3, 1 }, { 254, 1 }, { 7, 3 }, { 252, 3 }, { 15, 7 }, { 248, 7 }, { 31, 15 }, { 240, 15 }, { 63, 31 }, { 224, 31 }, { 127, 63 }, { 192, 63 }, { 255, 127 }, { 128, 127 }, { 127, 255 }, { 128, 255 }, }; /* entry[i] of the following tables gives * the number of VLC codes of length i + 2. */ static const uint16_t rv_lum_len_count[15] = { 1, 0, 2, 4, 8, 16, 32, 0, 64, 0, 128, 0, 256, 0, 512, }; static const uint16_t rv_chrom_len_count[15] = { 1, 2, 4, 0, 8, 0, 16, 0, 32, 0, 64, 0, 128, 0, 256, }; static VLC rv_dc_lum, rv_dc_chrom; int ff_rv_decode_dc(MpegEncContext *s, int n) { int code; if (n < 4) { code = get_vlc2(&s->gb, rv_dc_lum.table, DC_VLC_BITS, 2); } else { code = get_vlc2(&s->gb, rv_dc_chrom.table, DC_VLC_BITS, 2); if (code < 0) { av_log(s->avctx, AV_LOG_ERROR, "chroma dc error\n"); return -1; } } return code; } /* read RV 1.0 compatible frame header */ static int rv10_decode_picture_header(MpegEncContext *s) { int mb_count, pb_frame, marker, mb_xy; marker = get_bits1(&s->gb); if (get_bits1(&s->gb)) s->pict_type = AV_PICTURE_TYPE_P; else s->pict_type = AV_PICTURE_TYPE_I; if (!marker) av_log(s->avctx, AV_LOG_ERROR, "marker missing\n"); pb_frame = get_bits1(&s->gb); ff_dlog(s->avctx, "pict_type=%d pb_frame=%d\n", s->pict_type, pb_frame); if (pb_frame) { avpriv_request_sample(s->avctx, "PB-frame"); return AVERROR_PATCHWELCOME; } s->qscale = get_bits(&s->gb, 5); if (s->qscale == 0) { av_log(s->avctx, AV_LOG_ERROR, "Invalid qscale value: 0\n"); return AVERROR_INVALIDDATA; } if (s->pict_type == AV_PICTURE_TYPE_I) { if (s->rv10_version == 3) { /* specific MPEG like DC coding not used */ s->last_dc[0] = get_bits(&s->gb, 8); s->last_dc[1] = get_bits(&s->gb, 8); s->last_dc[2] = get_bits(&s->gb, 8); ff_dlog(s->avctx, "DC:%d %d %d\n", s->last_dc[0], s->last_dc[1], s->last_dc[2]); } } /* if multiple packets per frame are sent, the position at which * to display the macroblocks is coded here */ mb_xy = s->mb_x + s->mb_y * s->mb_width; if (show_bits(&s->gb, 12) == 0 || (mb_xy && mb_xy < s->mb_num)) { s->mb_x = get_bits(&s->gb, 6); /* mb_x */ s->mb_y = get_bits(&s->gb, 6); /* mb_y */ mb_count = get_bits(&s->gb, 12); } else { s->mb_x = 0; s->mb_y = 0; mb_count = s->mb_width * s->mb_height; } skip_bits(&s->gb, 3); /* ignored */ s->f_code = 1; return mb_count; } static int rv20_decode_picture_header(RVDecContext *rv, int whole_size) { MpegEncContext *s = &rv->m; int seq, mb_pos, i, ret; int rpr_max; i = get_bits(&s->gb, 2); switch (i) { case 0: s->pict_type = AV_PICTURE_TYPE_I; break; case 1: s->pict_type = AV_PICTURE_TYPE_I; break; // hmm ... case 2: s->pict_type = AV_PICTURE_TYPE_P; break; case 3: s->pict_type = AV_PICTURE_TYPE_B; break; default: av_log(s->avctx, AV_LOG_ERROR, "unknown frame type\n"); return AVERROR_INVALIDDATA; } if (s->low_delay && s->pict_type == AV_PICTURE_TYPE_B) { av_log(s->avctx, AV_LOG_ERROR, "low delay B\n"); return -1; } if (!s->last_picture_ptr && s->pict_type == AV_PICTURE_TYPE_B) { av_log(s->avctx, AV_LOG_ERROR, "early B-frame\n"); return AVERROR_INVALIDDATA; } if (get_bits1(&s->gb)) { av_log(s->avctx, AV_LOG_ERROR, "reserved bit set\n"); return AVERROR_INVALIDDATA; } s->qscale = get_bits(&s->gb, 5); if (s->qscale == 0) { av_log(s->avctx, AV_LOG_ERROR, "Invalid qscale value: 0\n"); return AVERROR_INVALIDDATA; } if (RV_GET_MINOR_VER(rv->sub_id) >= 2) s->loop_filter = get_bits1(&s->gb) && !s->avctx->lowres; if (RV_GET_MINOR_VER(rv->sub_id) <= 1) seq = get_bits(&s->gb, 8) << 7; else seq = get_bits(&s->gb, 13) << 2; rpr_max = s->avctx->extradata[1] & 7; if (rpr_max) { int f, new_w, new_h; int rpr_bits = av_log2(rpr_max) + 1; f = get_bits(&s->gb, rpr_bits); if (f) { if (s->avctx->extradata_size < 8 + 2 * f) { av_log(s->avctx, AV_LOG_ERROR, "Extradata too small.\n"); return AVERROR_INVALIDDATA; } new_w = 4 * ((uint8_t *) s->avctx->extradata)[6 + 2 * f]; new_h = 4 * ((uint8_t *) s->avctx->extradata)[7 + 2 * f]; } else { new_w = rv->orig_width; new_h = rv->orig_height; } if (new_w != s->width || new_h != s->height || !s->context_initialized) { AVRational old_aspect = s->avctx->sample_aspect_ratio; av_log(s->avctx, AV_LOG_DEBUG, "attempting to change resolution to %dx%d\n", new_w, new_h); if (av_image_check_size(new_w, new_h, 0, s->avctx) < 0) return AVERROR_INVALIDDATA; if (whole_size < (new_w + 15)/16 * ((new_h + 15)/16) / 8) return AVERROR_INVALIDDATA; ff_mpv_common_end(s); // attempt to keep aspect during typical resolution switches if (!old_aspect.num) old_aspect = (AVRational){1, 1}; if (2 * (int64_t)new_w * s->height == (int64_t)new_h * s->width) s->avctx->sample_aspect_ratio = av_mul_q(old_aspect, (AVRational){2, 1}); if ((int64_t)new_w * s->height == 2 * (int64_t)new_h * s->width) s->avctx->sample_aspect_ratio = av_mul_q(old_aspect, (AVRational){1, 2}); ret = ff_set_dimensions(s->avctx, new_w, new_h); if (ret < 0) return ret; s->width = new_w; s->height = new_h; if ((ret = ff_mpv_common_init(s)) < 0) return ret; } if (s->avctx->debug & FF_DEBUG_PICT_INFO) { av_log(s->avctx, AV_LOG_DEBUG, "F %d/%d/%d\n", f, rpr_bits, rpr_max); } } if (av_image_check_size(s->width, s->height, 0, s->avctx) < 0) return AVERROR_INVALIDDATA; mb_pos = ff_h263_decode_mba(s); seq |= s->time & ~0x7FFF; if (seq - s->time > 0x4000) seq -= 0x8000; if (seq - s->time < -0x4000) seq += 0x8000; if (seq != s->time) { if (s->pict_type != AV_PICTURE_TYPE_B) { s->time = seq; s->pp_time = s->time - s->last_non_b_time; s->last_non_b_time = s->time; } else { s->time = seq; s->pb_time = s->pp_time - (s->last_non_b_time - s->time); } } if (s->pict_type == AV_PICTURE_TYPE_B) { if (s->pp_time <=s->pb_time || s->pp_time <= s->pp_time - s->pb_time || s->pp_time<=0) { av_log(s->avctx, AV_LOG_DEBUG, "messed up order, possible from seeking? skipping current B-frame\n"); #define ERROR_SKIP_FRAME -123 return ERROR_SKIP_FRAME; } ff_mpeg4_init_direct_mv(s); } s->no_rounding = get_bits1(&s->gb); if (RV_GET_MINOR_VER(rv->sub_id) <= 1 && s->pict_type == AV_PICTURE_TYPE_B) // binary decoder reads 3+2 bits here but they don't seem to be used skip_bits(&s->gb, 5); s->f_code = 1; s->h263_aic = s->pict_type == AV_PICTURE_TYPE_I; s->modified_quant = 1; if (!s->avctx->lowres) s->loop_filter = 1; if (s->avctx->debug & FF_DEBUG_PICT_INFO) { av_log(s->avctx, AV_LOG_INFO, "num:%5d x:%2d y:%2d type:%d qscale:%2d rnd:%d\n", seq, s->mb_x, s->mb_y, s->pict_type, s->qscale, s->no_rounding); } av_assert0(s->pict_type != AV_PICTURE_TYPE_B || !s->low_delay); return s->mb_width * s->mb_height - mb_pos; } static av_cold void rv10_build_vlc(VLC *vlc, const uint16_t len_count[15], const uint8_t sym_rl[][2], int sym_rl_elems) { uint16_t syms[MAX_VLC_ENTRIES]; uint8_t lens[MAX_VLC_ENTRIES]; unsigned nb_syms = 0, nb_lens = 0; for (unsigned i = 0; i < sym_rl_elems; i++) { unsigned cur_sym = sym_rl[i][0]; for (unsigned tmp = nb_syms + sym_rl[i][1]; nb_syms <= tmp; nb_syms++) syms[nb_syms] = 0xFF & cur_sym--; } for (unsigned i = 0; i < 15; i++) for (unsigned tmp = nb_lens + len_count[i]; nb_lens < tmp; nb_lens++) lens[nb_lens] = i + 2; av_assert1(nb_lens == nb_syms); ff_vlc_init_from_lengths(vlc, DC_VLC_BITS, nb_lens, lens, 1, syms, 2, 2, 0, VLC_INIT_STATIC_OVERLONG, NULL); } static av_cold void rv10_init_static(void) { static VLCElem table[1472 + 992]; rv_dc_lum.table = table; rv_dc_lum.table_allocated = 1472; rv10_build_vlc(&rv_dc_lum, rv_lum_len_count, rv_sym_run_len, FF_ARRAY_ELEMS(rv_sym_run_len)); for (int i = 0; i < 1 << (DC_VLC_BITS - 7 /* Length of skip prefix */); i++) { /* All codes beginning with 0x7F have the same length and value. * Modifying the table directly saves us the useless subtables. */ rv_dc_lum.table[(0x7F << (DC_VLC_BITS - 7)) + i].sym = 255; rv_dc_lum.table[(0x7F << (DC_VLC_BITS - 7)) + i].len = 18; } rv_dc_chrom.table = &table[1472]; rv_dc_chrom.table_allocated = 992; rv10_build_vlc(&rv_dc_chrom, rv_chrom_len_count, rv_sym_run_len, FF_ARRAY_ELEMS(rv_sym_run_len) - 2); for (int i = 0; i < 1 << (DC_VLC_BITS - 9 /* Length of skip prefix */); i++) { /* Same as above. */ rv_dc_chrom.table[(0x1FE << (DC_VLC_BITS - 9)) + i].sym = 255; rv_dc_chrom.table[(0x1FE << (DC_VLC_BITS - 9)) + i].len = 18; } ff_h263_decode_init_vlc(); } static av_cold int rv10_decode_init(AVCodecContext *avctx) { static AVOnce init_static_once = AV_ONCE_INIT; RVDecContext *rv = avctx->priv_data; MpegEncContext *s = &rv->m; int major_ver, minor_ver, micro_ver, ret; if (avctx->extradata_size < 8) { av_log(avctx, AV_LOG_ERROR, "Extradata is too small.\n"); return AVERROR_INVALIDDATA; } if ((ret = av_image_check_size(avctx->coded_width, avctx->coded_height, 0, avctx)) < 0) return ret; ff_mpv_decode_init(s, avctx); s->out_format = FMT_H263; rv->orig_width = s->width = avctx->coded_width; rv->orig_height = s->height = avctx->coded_height; s->h263_long_vectors = ((uint8_t *) avctx->extradata)[3] & 1; rv->sub_id = AV_RB32((uint8_t *) avctx->extradata + 4); major_ver = RV_GET_MAJOR_VER(rv->sub_id); minor_ver = RV_GET_MINOR_VER(rv->sub_id); micro_ver = RV_GET_MICRO_VER(rv->sub_id); s->low_delay = 1; switch (major_ver) { case 1: s->rv10_version = micro_ver ? 3 : 1; s->obmc = micro_ver == 2; break; case 2: if (minor_ver >= 2) { s->low_delay = 0; s->avctx->has_b_frames = 1; } break; default: av_log(s->avctx, AV_LOG_ERROR, "unknown header %X\n", rv->sub_id); avpriv_request_sample(avctx, "RV1/2 version"); return AVERROR_PATCHWELCOME; } if (avctx->debug & FF_DEBUG_PICT_INFO) { av_log(avctx, AV_LOG_DEBUG, "ver:%X ver0:%"PRIX32"\n", rv->sub_id, ((uint32_t *) avctx->extradata)[0]); } avctx->pix_fmt = AV_PIX_FMT_YUV420P; ff_mpv_idct_init(s); if ((ret = ff_mpv_common_init(s)) < 0) return ret; ff_h263dsp_init(&s->h263dsp); /* init static VLCs */ ff_thread_once(&init_static_once, rv10_init_static); return 0; } static av_cold int rv10_decode_end(AVCodecContext *avctx) { MpegEncContext *s = avctx->priv_data; ff_mpv_common_end(s); return 0; } static int rv10_decode_packet(AVCodecContext *avctx, const uint8_t *buf, int buf_size, int buf_size2, int whole_size) { RVDecContext *rv = avctx->priv_data; MpegEncContext *s = &rv->m; int mb_count, mb_pos, left, start_mb_x, active_bits_size, ret; active_bits_size = buf_size * 8; init_get_bits(&s->gb, buf, FFMAX(buf_size, buf_size2) * 8); if (s->codec_id == AV_CODEC_ID_RV10) mb_count = rv10_decode_picture_header(s); else mb_count = rv20_decode_picture_header(rv, whole_size); if (mb_count < 0) { if (mb_count != ERROR_SKIP_FRAME) av_log(s->avctx, AV_LOG_ERROR, "HEADER ERROR\n"); return AVERROR_INVALIDDATA; } if (s->mb_x >= s->mb_width || s->mb_y >= s->mb_height) { av_log(s->avctx, AV_LOG_ERROR, "POS ERROR %d %d\n", s->mb_x, s->mb_y); return AVERROR_INVALIDDATA; } mb_pos = s->mb_y * s->mb_width + s->mb_x; left = s->mb_width * s->mb_height - mb_pos; if (mb_count > left) { av_log(s->avctx, AV_LOG_ERROR, "COUNT ERROR\n"); return AVERROR_INVALIDDATA; } if (whole_size < s->mb_width * s->mb_height / 8) return AVERROR_INVALIDDATA; if ((s->mb_x == 0 && s->mb_y == 0) || !s->current_picture_ptr) { // FIXME write parser so we always have complete frames? if (s->current_picture_ptr) { ff_er_frame_end(&s->er, NULL); ff_mpv_frame_end(s); s->mb_x = s->mb_y = s->resync_mb_x = s->resync_mb_y = 0; } if ((ret = ff_mpv_frame_start(s, avctx)) < 0) return ret; ff_mpeg_er_frame_start(s); } else { if (s->current_picture_ptr->f->pict_type != s->pict_type) { av_log(s->avctx, AV_LOG_ERROR, "Slice type mismatch\n"); return AVERROR_INVALIDDATA; } } ff_dlog(avctx, "qscale=%d\n", s->qscale); /* default quantization values */ if (s->codec_id == AV_CODEC_ID_RV10) { if (s->mb_y == 0) s->first_slice_line = 1; } else { s->first_slice_line = 1; s->resync_mb_x = s->mb_x; } start_mb_x = s->mb_x; s->resync_mb_y = s->mb_y; if (s->h263_aic) { s->y_dc_scale_table = s->c_dc_scale_table = ff_aic_dc_scale_table; } else { s->y_dc_scale_table = s->c_dc_scale_table = ff_mpeg1_dc_scale_table; } if (s->modified_quant) s->chroma_qscale_table = ff_h263_chroma_qscale_table; ff_set_qscale(s, s->qscale); s->rv10_first_dc_coded[0] = 0; s->rv10_first_dc_coded[1] = 0; s->rv10_first_dc_coded[2] = 0; s->block_wrap[0] = s->block_wrap[1] = s->block_wrap[2] = s->block_wrap[3] = s->b8_stride; s->block_wrap[4] = s->block_wrap[5] = s->mb_stride; ff_init_block_index(s); /* decode each macroblock */ for (s->mb_num_left = mb_count; s->mb_num_left > 0; s->mb_num_left--) { int ret; ff_update_block_index(s, 8, s->avctx->lowres, 1); ff_tlog(avctx, "**mb x=%d y=%d\n", s->mb_x, s->mb_y); s->mv_dir = MV_DIR_FORWARD; s->mv_type = MV_TYPE_16X16; ret = ff_h263_decode_mb(s, s->block); // Repeat the slice end check from ff_h263_decode_mb with our active // bitstream size if (ret != SLICE_ERROR && active_bits_size >= get_bits_count(&s->gb)) { int v = show_bits(&s->gb, 16); if (get_bits_count(&s->gb) + 16 > active_bits_size) v >>= get_bits_count(&s->gb) + 16 - active_bits_size; if (!v) ret = SLICE_END; } if (ret != SLICE_ERROR && active_bits_size < get_bits_count(&s->gb) && 8 * buf_size2 >= get_bits_count(&s->gb)) { active_bits_size = buf_size2 * 8; av_log(avctx, AV_LOG_DEBUG, "update size from %d to %d\n", 8 * buf_size, active_bits_size); ret = SLICE_OK; } if (ret == SLICE_ERROR || active_bits_size < get_bits_count(&s->gb)) { av_log(s->avctx, AV_LOG_ERROR, "ERROR at MB %d %d\n", s->mb_x, s->mb_y); return AVERROR_INVALIDDATA; } if (s->pict_type != AV_PICTURE_TYPE_B) ff_h263_update_motion_val(s); ff_mpv_reconstruct_mb(s, s->block); if (s->loop_filter) ff_h263_loop_filter(s); if (++s->mb_x == s->mb_width) { s->mb_x = 0; s->mb_y++; ff_init_block_index(s); } if (s->mb_x == s->resync_mb_x) s->first_slice_line = 0; if (ret == SLICE_END) break; } ff_er_add_slice(&s->er, start_mb_x, s->resync_mb_y, s->mb_x - 1, s->mb_y, ER_MB_END); return active_bits_size; } static int get_slice_offset(AVCodecContext *avctx, const uint8_t *buf, int n) { return AV_RL32(buf + n * 8); } static int rv10_decode_frame(AVCodecContext *avctx, AVFrame *pict, int *got_frame, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MpegEncContext *s = avctx->priv_data; int i, ret; int slice_count; const uint8_t *slices_hdr = NULL; ff_dlog(avctx, "*****frame %"PRId64" size=%d\n", avctx->frame_num, buf_size); /* no supplementary picture */ if (buf_size == 0) { return 0; } slice_count = (*buf++) + 1; buf_size--; if (!slice_count || buf_size <= 8 * slice_count) { av_log(avctx, AV_LOG_ERROR, "Invalid slice count: %d.\n", slice_count); return AVERROR_INVALIDDATA; } slices_hdr = buf + 4; buf += 8 * slice_count; buf_size -= 8 * slice_count; for (i = 0; i < slice_count; i++) { unsigned offset = get_slice_offset(avctx, slices_hdr, i); int size, size2; if (offset >= buf_size) return AVERROR_INVALIDDATA; if (i + 1 == slice_count) size = buf_size - offset; else size = get_slice_offset(avctx, slices_hdr, i + 1) - offset; if (i + 2 >= slice_count) size2 = buf_size - offset; else size2 = get_slice_offset(avctx, slices_hdr, i + 2) - offset; if (size <= 0 || size2 <= 0 || offset + FFMAX(size, size2) > buf_size) return AVERROR_INVALIDDATA; if ((ret = rv10_decode_packet(avctx, buf + offset, size, size2, buf_size)) < 0) return ret; if (ret > 8 * size) i++; } if (s->current_picture_ptr && s->mb_y >= s->mb_height) { ff_er_frame_end(&s->er, NULL); ff_mpv_frame_end(s); if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) { if ((ret = av_frame_ref(pict, s->current_picture_ptr->f)) < 0) return ret; ff_print_debug_info(s, s->current_picture_ptr, pict); ff_mpv_export_qp_table(s, pict, s->current_picture_ptr, FF_MPV_QSCALE_TYPE_MPEG1); } else if (s->last_picture_ptr) { if ((ret = av_frame_ref(pict, s->last_picture_ptr->f)) < 0) return ret; ff_print_debug_info(s, s->last_picture_ptr, pict); ff_mpv_export_qp_table(s, pict,s->last_picture_ptr, FF_MPV_QSCALE_TYPE_MPEG1); } if (s->last_picture_ptr || s->low_delay) { *got_frame = 1; } // so we can detect if frame_end was not called (find some nicer solution...) s->current_picture_ptr = NULL; } return avpkt->size; } const FFCodec ff_rv10_decoder = { .p.name = "rv10", CODEC_LONG_NAME("RealVideo 1.0"), .p.type = AVMEDIA_TYPE_VIDEO, .p.id = AV_CODEC_ID_RV10, .priv_data_size = sizeof(RVDecContext), .init = rv10_decode_init, .close = rv10_decode_end, FF_CODEC_DECODE_CB(rv10_decode_frame), .p.capabilities = AV_CODEC_CAP_DR1, .p.max_lowres = 3, .p.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE }, }; const FFCodec ff_rv20_decoder = { .p.name = "rv20", CODEC_LONG_NAME("RealVideo 2.0"), .p.type = AVMEDIA_TYPE_VIDEO, .p.id = AV_CODEC_ID_RV20, .priv_data_size = sizeof(RVDecContext), .init = rv10_decode_init, .close = rv10_decode_end, FF_CODEC_DECODE_CB(rv10_decode_frame), .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY, .flush = ff_mpeg_flush, .p.max_lowres = 3, .p.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE }, };