avcodec: add Media 100i decoder

1 files changed, 224 insertions, 0 deletions

diff --git a/libavcodec/media100.c b/libavcodec/media100.c
new file mode 100644
index 0000000000..fdfce2cac1
--- /dev/null
+++ b/libavcodec/media100.c
@@ -0,0 +1,224 @@
+/*
+ * Media 100 decoder
+ * Copyright (c) 2022 Paul B Mahol
+ *
+ * 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
+ * Media 100 decoder.
+ */
+
+#include <inttypes.h>
+
+#include "libavutil/intreadwrite.h"
+#include "avcodec.h"
+#include "bytestream.h"
+#include "codec_internal.h"
+
+typedef struct Media100Context {
+    AVCodecContext *avctx;   // wrapper context for mjpegb
+    AVPacket *pkt;
+} Media100Context;
+
+static av_cold int media100_decode_init(AVCodecContext *avctx)
+{
+    Media100Context *ctx = avctx->priv_data;
+    const AVCodec *codec;
+    int ret;
+
+    codec = avcodec_find_decoder(AV_CODEC_ID_MJPEGB);
+    if (!codec)
+        return AVERROR_BUG;
+    ctx->avctx = avcodec_alloc_context3(codec);
+    if (!ctx->avctx)
+        return AVERROR(ENOMEM);
+    ctx->avctx->thread_count = 1;
+    ctx->avctx->flags  = avctx->flags;
+    ctx->avctx->flags2 = avctx->flags2;
+    ctx->avctx->width  = ctx->avctx->coded_width  = avctx->width;
+    ctx->avctx->height = ctx->avctx->coded_height = avctx->height;
+
+    ret = avcodec_open2(ctx->avctx, codec, NULL);
+    if (ret < 0)
+        return ret;
+
+    ctx->pkt = av_packet_alloc();
+    if (!ctx->pkt)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static int media100_decode_frame(AVCodecContext *avctx,
+                                 AVFrame *frame, int *got_frame,
+                                 AVPacket *avpkt)
+{
+    Media100Context *ctx = avctx->priv_data;
+    unsigned second_field_offset = 0;
+    unsigned next_field = 0;
+    unsigned dht_offset[2];
+    unsigned dqt_offset[2];
+    unsigned sod_offset[2];
+    unsigned sof_offset[2];
+    unsigned sos_offset[2];
+    unsigned field = 0;
+    GetByteContext gb;
+    PutByteContext pb;
+    AVPacket *pkt;
+    int ret;
+
+    if (avpkt->size + 1024 > ctx->pkt->size) {
+        ret = av_grow_packet(ctx->pkt, avpkt->size + 1024 - ctx->pkt->size);
+        if (ret < 0)
+            return ret;
+    }
+
+    ret = av_packet_make_writable(ctx->pkt);
+    if (ret < 0)
+        return ret;
+
+    bytestream2_init(&gb, avpkt->data, avpkt->size);
+    bytestream2_init_writer(&pb, ctx->pkt->data, ctx->pkt->size);
+
+second_field:
+    bytestream2_put_be32(&pb, 0);
+    bytestream2_put_be32(&pb, AV_RB32("mjpg"));
+    bytestream2_put_be32(&pb, 0);
+    bytestream2_put_be32(&pb, 0);
+    for (int i = 0; i < 6; i++)
+        bytestream2_put_be32(&pb, 0);
+
+    sof_offset[field] = bytestream2_tell_p(&pb);
+    bytestream2_put_be16(&pb, 17);
+    bytestream2_put_byte(&pb, 8);
+    bytestream2_put_be16(&pb, avctx->height / 2);
+    bytestream2_put_be16(&pb, avctx->width);
+    bytestream2_put_byte(&pb, 3);
+    bytestream2_put_byte(&pb, 1);
+    bytestream2_put_byte(&pb, 0x21);
+    bytestream2_put_byte(&pb, 0);
+    bytestream2_put_byte(&pb, 2);
+    bytestream2_put_byte(&pb, 0x11);
+    bytestream2_put_byte(&pb, 1);
+    bytestream2_put_byte(&pb, 3);
+    bytestream2_put_byte(&pb, 0x11);
+    bytestream2_put_byte(&pb, 1);
+
+    sos_offset[field] = bytestream2_tell_p(&pb);
+    bytestream2_put_be16(&pb, 12);
+    bytestream2_put_byte(&pb, 3);
+    bytestream2_put_byte(&pb, 1);
+    bytestream2_put_byte(&pb, 0);
+    bytestream2_put_byte(&pb, 2);
+    bytestream2_put_byte(&pb, 0x11);
+    bytestream2_put_byte(&pb, 3);
+    bytestream2_put_byte(&pb, 0x11);
+    bytestream2_put_byte(&pb, 0);
+    bytestream2_put_byte(&pb, 0);
+    bytestream2_put_byte(&pb, 0);
+
+    dqt_offset[field] = bytestream2_tell_p(&pb);
+    bytestream2_put_be16(&pb, 132);
+    bytestream2_put_byte(&pb, 0);
+    bytestream2_skip(&gb, 4);
+    for (int i = 0; i < 64; i++)
+        bytestream2_put_byte(&pb, bytestream2_get_be32(&gb));
+    bytestream2_put_byte(&pb, 1);
+    for (int i = 0; i < 64; i++)
+        bytestream2_put_byte(&pb, bytestream2_get_be32(&gb));
+
+    dht_offset[field] = 0;
+    sod_offset[field] = bytestream2_tell_p(&pb);
+
+    for (int i = bytestream2_tell(&gb) + 8; next_field == 0 && i < avpkt->size - 4; i++) {
+        if (AV_RB32(avpkt->data + i) == 0x00000001) {
+            next_field = i;
+            break;
+        }
+    }
+
+    bytestream2_skip(&gb, 8);
+    bytestream2_copy_buffer(&pb, &gb, next_field - bytestream2_tell(&gb));
+    bytestream2_put_be64(&pb, 0);
+
+    if (field == 0) {
+        field = 1;
+        second_field_offset = bytestream2_tell_p(&pb);
+        next_field = avpkt->size;
+        goto second_field;
+    }
+
+    pkt = ctx->pkt;
+
+    AV_WB32(pkt->data +  8, second_field_offset);
+    AV_WB32(pkt->data + 12, second_field_offset);
+    AV_WB32(pkt->data + 16, second_field_offset);
+    AV_WB32(pkt->data + 20, dqt_offset[0]);
+    AV_WB32(pkt->data + 24, dht_offset[0]);
+    AV_WB32(pkt->data + 28, sof_offset[0]);
+    AV_WB32(pkt->data + 32, sos_offset[0]);
+    AV_WB32(pkt->data + 36, sod_offset[0]);
+
+    AV_WB32(pkt->data + second_field_offset +  8, bytestream2_tell_p(&pb) - second_field_offset);
+    AV_WB32(pkt->data + second_field_offset + 12, bytestream2_tell_p(&pb) - second_field_offset);
+    AV_WB32(pkt->data + second_field_offset + 16, 0);
+    AV_WB32(pkt->data + second_field_offset + 20, dqt_offset[1] - second_field_offset);
+    AV_WB32(pkt->data + second_field_offset + 24, dht_offset[1]);
+    AV_WB32(pkt->data + second_field_offset + 28, sof_offset[1] - second_field_offset);
+    AV_WB32(pkt->data + second_field_offset + 32, sos_offset[1] - second_field_offset);
+    AV_WB32(pkt->data + second_field_offset + 36, sod_offset[1] - second_field_offset);
+
+    pkt->size = bytestream2_tell_p(&pb);
+
+    ret = avcodec_send_packet(ctx->avctx, pkt);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Error submitting a packet for decoding\n");
+        return ret;
+    }
+
+    ret = avcodec_receive_frame(ctx->avctx, frame);
+    if (ret < 0)
+        return ret;
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int media100_decode_end(AVCodecContext *avctx)
+{
+    Media100Context *ctx = avctx->priv_data;
+
+    avcodec_free_context(&ctx->avctx);
+    av_packet_free(&ctx->pkt);
+
+    return 0;
+}
+
+const FFCodec ff_media100_decoder = {
+    .p.name           = "media100",
+    CODEC_LONG_NAME("Media 100"),
+    .p.type           = AVMEDIA_TYPE_VIDEO,
+    .p.id             = AV_CODEC_ID_MEDIA100,
+    .priv_data_size   = sizeof(Media100Context),
+    .init             = media100_decode_init,
+    .close            = media100_decode_end,
+    FF_CODEC_DECODE_CB(media100_decode_frame),
+    .caps_internal    = FF_CODEC_CAP_INIT_CLEANUP,
+};