avcodec: add media100_to_mjpegb bitstream filter and use it

1 files changed, 168 insertions, 0 deletions

diff --git a/libavcodec/media100_to_mjpegb_bsf.c b/libavcodec/media100_to_mjpegb_bsf.c
new file mode 100644
index 0000000000..6e117ae20f
--- /dev/null
+++ b/libavcodec/media100_to_mjpegb_bsf.c
@@ -0,0 +1,168 @@
+/*
+ * Media 100 to MJPEGB bitstream filter
+ * Copyright (c) 2023 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 to MJPEGB bitstream filter.
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "bsf.h"
+#include "bsf_internal.h"
+#include "bytestream.h"
+
+static av_cold int init(AVBSFContext *ctx)
+{
+    ctx->par_out->codec_id = AV_CODEC_ID_MJPEGB;
+    return 0;
+}
+
+static int filter(AVBSFContext *ctx, AVPacket *out)
+{
+    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 *in;
+    int ret;
+
+    ret = ff_bsf_get_packet(ctx, &in);
+    if (ret < 0)
+        return ret;
+
+    ret = av_new_packet(out, in->size + 1024);
+    if (ret < 0)
+        goto fail;
+
+    bytestream2_init(&gb, in->data, in->size);
+    bytestream2_init_writer(&pb, out->data, out->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, ctx->par_in->height / 2);
+    bytestream2_put_be16(&pb, ctx->par_in->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 < in->size - 4; i++) {
+        if (AV_RB32(in->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 = in->size;
+        goto second_field;
+    }
+
+    AV_WB32(out->data +  8, second_field_offset);
+    AV_WB32(out->data + 12, second_field_offset);
+    AV_WB32(out->data + 16, second_field_offset);
+    AV_WB32(out->data + 20, dqt_offset[0]);
+    AV_WB32(out->data + 24, dht_offset[0]);
+    AV_WB32(out->data + 28, sof_offset[0]);
+    AV_WB32(out->data + 32, sos_offset[0]);
+    AV_WB32(out->data + 36, sod_offset[0]);
+
+    AV_WB32(out->data + second_field_offset +  8, bytestream2_tell_p(&pb) - second_field_offset);
+    AV_WB32(out->data + second_field_offset + 12, bytestream2_tell_p(&pb) - second_field_offset);
+    AV_WB32(out->data + second_field_offset + 16, 0);
+    AV_WB32(out->data + second_field_offset + 20, dqt_offset[1] - second_field_offset);
+    AV_WB32(out->data + second_field_offset + 24, dht_offset[1]);
+    AV_WB32(out->data + second_field_offset + 28, sof_offset[1] - second_field_offset);
+    AV_WB32(out->data + second_field_offset + 32, sos_offset[1] - second_field_offset);
+    AV_WB32(out->data + second_field_offset + 36, sod_offset[1] - second_field_offset);
+
+    out->size = bytestream2_tell_p(&pb);
+
+    ret = av_packet_copy_props(out, in);
+    if (ret < 0)
+        goto fail;
+
+fail:
+    if (ret < 0)
+        av_packet_unref(out);
+    av_packet_free(&in);
+    return ret;
+}
+
+const FFBitStreamFilter ff_media100_to_mjpegb_bsf = {
+    .p.name         = "media100_to_mjpegb",
+    .p.codec_ids    = (const enum AVCodecID []){ AV_CODEC_ID_MEDIA100, AV_CODEC_ID_NONE },
+    .init           = init,
+    .filter         = filter,
+};