static int encode_apng(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet) { PNGEncContext *s = avctx->priv_data; int ret; int enc_row_size; size_t max_packet_size; APNGFctlChunk fctl_chunk = {0}; if (pict && avctx->codec_id == AV_CODEC_ID_APNG && s->color_type == PNG_COLOR_TYPE_PALETTE) { uint32_t checksum = ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, pict->data[1], 256 * sizeof(uint32_t)); if (avctx->frame_number == 0) { s->palette_checksum = checksum; } else if (checksum != s->palette_checksum) { av_log(avctx, AV_LOG_ERROR, "Input contains more than one unique palette. APNG does not support multiple palettes.\n"); return -1; } } enc_row_size = deflateBound(&s->zstream, (avctx->width * s->bits_per_pixel + 7) >> 3); max_packet_size = AV_INPUT_BUFFER_MIN_SIZE + // headers avctx->height * ( enc_row_size + (4 + 12) * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // fdAT * ceil(enc_row_size / IOBUF_SIZE) ); if (max_packet_size > INT_MAX) return AVERROR(ENOMEM); if (avctx->frame_number == 0) { if (!pict) return AVERROR(EINVAL); s->bytestream = avctx->extradata = av_malloc(FF_MIN_BUFFER_SIZE); if (!avctx->extradata) return AVERROR(ENOMEM); ret = encode_headers(avctx, pict); if (ret < 0) return ret; avctx->extradata_size = s->bytestream - avctx->extradata; s->last_frame_packet = av_malloc(max_packet_size); if (!s->last_frame_packet) return AVERROR(ENOMEM); } else if (s->last_frame) { ret = ff_alloc_packet2(avctx, pkt, max_packet_size, 0); if (ret < 0) return ret; memcpy(pkt->data, s->last_frame_packet, s->last_frame_packet_size); pkt->size = s->last_frame_packet_size; pkt->pts = pkt->dts = s->last_frame->pts; } if (pict) { s->bytestream_start = s->bytestream = s->last_frame_packet; s->bytestream_end = s->bytestream + max_packet_size; // We're encoding the frame first, so we have to do a bit of shuffling around // to have the image data write to the correct place in the buffer fctl_chunk.sequence_number = s->sequence_number; ++s->sequence_number; s->bytestream += 26 + 12; ret = apng_encode_frame(avctx, pict, &fctl_chunk, &s->last_frame_fctl); if (ret < 0) return ret; fctl_chunk.delay_num = 0; // delay filled in during muxing fctl_chunk.delay_den = 0; } else { s->last_frame_fctl.dispose_op = APNG_DISPOSE_OP_NONE; } if (s->last_frame) { uint8_t* last_fctl_chunk_start = pkt->data; uint8_t buf[26]; AV_WB32(buf + 0, s->last_frame_fctl.sequence_number); AV_WB32(buf + 4, s->last_frame_fctl.width); AV_WB32(buf + 8, s->last_frame_fctl.height); AV_WB32(buf + 12, s->last_frame_fctl.x_offset); AV_WB32(buf + 16, s->last_frame_fctl.y_offset); AV_WB16(buf + 20, s->last_frame_fctl.delay_num); AV_WB16(buf + 22, s->last_frame_fctl.delay_den); buf[24] = s->last_frame_fctl.dispose_op; buf[25] = s->last_frame_fctl.blend_op; png_write_chunk(&last_fctl_chunk_start, MKTAG('f', 'c', 'T', 'L'), buf, 26); *got_packet = 1; } if (pict) { if (!s->last_frame) { s->last_frame = av_frame_alloc(); if (!s->last_frame) return AVERROR(ENOMEM); } else if (s->last_frame_fctl.dispose_op != APNG_DISPOSE_OP_PREVIOUS) { if (!s->prev_frame) { s->prev_frame = av_frame_alloc(); if (!s->prev_frame) return AVERROR(ENOMEM); s->prev_frame->format = pict->format; s->prev_frame->width = pict->width; s->prev_frame->height = pict->height; if ((ret = av_frame_get_buffer(s->prev_frame, 32)) < 0) return ret; } // Do disposal, but not blending memcpy(s->prev_frame->data[0], s->last_frame->data[0], s->last_frame->linesize[0] * s->last_frame->height); if (s->last_frame_fctl.dispose_op == APNG_DISPOSE_OP_BACKGROUND) { uint32_t y; uint8_t bpp = (s->bits_per_pixel + 7) >> 3; for (y = s->last_frame_fctl.y_offset; y < s->last_frame_fctl.y_offset + s->last_frame_fctl.height; ++y) { size_t row_start = s->last_frame->linesize[0] * y + bpp * s->last_frame_fctl.x_offset; memset(s->prev_frame->data[0] + row_start, 0, bpp * s->last_frame_fctl.width); } } } av_frame_unref(s->last_frame); ret = av_frame_ref(s->last_frame, (AVFrame*)pict); if (ret < 0) return ret; s->last_frame_fctl = fctl_chunk; s->last_frame_packet_size = s->bytestream - s->bytestream_start; } else { av_frame_free(&s->last_frame); } return 0; }