mpegts: Fix JPEG-XS Extension Descriptor handling

The initial specification for the descriptor (from H.222.0 06/21) was wrong and
introduced duplicate descriptor_tag/descriptor_length field.

This was later corrected in H.222.0 (2021) Amendment 1 (12/22)

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/3945

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7775>
This commit is contained in:
Edward Hervey 2024-10-29 09:43:11 +01:00 committed by GStreamer Marge Bot
parent 35e19134d1
commit fb16abcd73

View file

@ -1584,11 +1584,12 @@ gst_mpegts_descriptor_parse_jpeg_xs (const GstMpegtsDescriptor * descriptor,
guint8 flags;
g_return_val_if_fail (descriptor != NULL && res != NULL, FALSE);
/* The smallest jpegxs descriptor doesn't contain the MDM, but is an H.222.0 extension (so additional one byte) */
__common_desc_ext_checks (descriptor, GST_MTS_DESC_EXT_JXS_VIDEO, 32, FALSE);
/* The smallest jpegxs descriptor doesn't contain the MDM,
* but is an H.222.0 extension (so additional one byte) */
__common_desc_ext_checks (descriptor, GST_MTS_DESC_EXT_JXS_VIDEO, 30, FALSE);
/* Skip tag/length/extension/tag/length */
gst_byte_reader_init (&br, descriptor->data + 5, descriptor->length - 3);
/* Skip tag/length/extension */
gst_byte_reader_init (&br, descriptor->data + 3, descriptor->length - 1);
memset (res, 0, sizeof (*res));
/* First part can be scanned out with unchecked reader */
@ -1650,24 +1651,13 @@ gst_mpegts_descriptor_parse_jpeg_xs (const GstMpegtsDescriptor * descriptor,
GstMpegtsDescriptor *
gst_mpegts_descriptor_from_jpeg_xs (const GstMpegtsJpegXsDescriptor * jpegxs)
{
gsize desc_size = 30;
gsize desc_size = 29;
GstByteWriter writer;
guint8 *desc_data;
GstMpegtsDescriptor *descriptor;
/* Extension descriptor
* tag/length are take care of by gst_mpegts_descriptor_from_custom
* The size of the "internal" descriptor (in the extension) is 1 (for the extension_descriptor_tag) and 29 for JXS_video_descriptor
*/
gst_byte_writer_init_with_size (&writer, desc_size, FALSE);
/* extension tag */
gst_byte_writer_put_uint8 (&writer, GST_MTS_DESC_EXT_JXS_VIDEO);
/* tag/length again */
gst_byte_writer_put_uint8 (&writer, GST_MTS_DESC_EXT_JXS_VIDEO);
/* Size is 27 (29 minus 2 initial bytes for tag/length */
gst_byte_writer_put_uint8 (&writer, 27);
/* descriptor version: 0 */
gst_byte_writer_put_uint8 (&writer, 0);
/* horizontal/vertical size */
@ -1709,11 +1699,12 @@ gst_mpegts_descriptor_from_jpeg_xs (const GstMpegtsJpegXsDescriptor * jpegxs)
}
desc_size = gst_byte_writer_get_size (&writer);
g_assert (desc_size == 29);
desc_data = gst_byte_writer_reset_and_get_data (&writer);
descriptor =
gst_mpegts_descriptor_from_custom (GST_MTS_DESC_EXTENSION, desc_data,
desc_size);
gst_mpegts_descriptor_from_custom_with_extension (GST_MTS_DESC_EXTENSION,
GST_MTS_DESC_EXT_JXS_VIDEO, desc_data, desc_size);
g_free (desc_data);
return descriptor;