Re: [FFmpeg-devel] [PATCH] Encrypted SMPTE DC MXF - additional UL needed to unpack EKLV packet

[Richard Ayres <Richard.Ayres@bydeluxe.com>]

Thanks, Pierre-Anthony. I've updated the patch to remove the unnecessary UL and it's now using mxf_match_uid() to detect the EKLV packet.

Signed-off-by: Richard Ayres <richard.ayres@bydeluxe.com>
---
 libavformat/mxfdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index badd2be224..b1ab90f25f 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -3737,7 +3737,7 @@ static int mxf_read_header(AVFormatContext *s)

         PRINT_KEY(s, "read header", klv.key);
         av_log(s, AV_LOG_TRACE, "size %"PRIu64" offset %#"PRIx64"\n", klv.length, klv.offset);
-        if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key) ||
+        if (mxf_match_uid(klv.key, mxf_encrypted_triplet_key, sizeof(mxf_encrypted_triplet_key)) ||
             IS_KLV_KEY(klv.key, mxf_essence_element_key) ||
             IS_KLV_KEY(klv.key, mxf_canopus_essence_element_key) ||
             IS_KLV_KEY(klv.key, mxf_avid_essence_element_key) ||
@@ -3983,7 +3983,7 @@ static int mxf_read_packet(AVFormatContext *s, AVPacket *pkt)
             pos = klv.next_klv - klv.length;
             PRINT_KEY(s, "read packet", klv.key);
             av_log(s, AV_LOG_TRACE, "size %"PRIu64" offset %#"PRIx64"\n", klv.length, klv.offset);
-            if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key)) {
+            if (mxf_match_uid(klv.key, mxf_encrypted_triplet_key, sizeof(mxf_encrypted_triplet_key))) {
                 ret = mxf_decrypt_triplet(s, pkt, &klv);
                 if (ret < 0) {
                     av_log(s, AV_LOG_ERROR, "invalid encoded triplet\n");
--
2.25.1



________________________________________
From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> on behalf of Pierre-Anthony Lemieux <pal@sandflow.com>
Sent: 30 September 2022 15:31
To: FFmpeg development discussions and patches
Subject: Re: [FFmpeg-devel] [PATCH] Encrypted SMPTE DC MXF - additional UL needed to unpack EKLV packet

[ CAUTION ]

This email originated outside Deluxe.



On Fri, Sep 30, 2022 at 7:08 AM Richard Ayres
<Richard.Ayres@bydeluxe.com> wrote:
>
> We had an issue where ffmpeg was unable to unpack the EKLV of an encrypted 3D SMPTE DC MXF.
>
> The patch adds the SMPTE UL for EKLV packets (060e2b34.02040101.0d010301.027e0100), to mxfdec.c in order to unpack an EKLV packet found within an Encrypted SMPTE Digital Cinema MXF.
>
> Signed-off-by: Richard Ayres <richard.ayres@bydeluxe.com>
> ---
>  libavformat/mxfdec.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index badd2be224..ebd64b1c68 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -343,6 +343,7 @@ static const uint8_t mxf_apple_coll_prefix[]               = { 0x06,0x0e,0x2b,0x
>  /* complete keys to match */
>  static const uint8_t mxf_crypto_source_container_ul[]      = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x09,0x06,0x01,0x01,0x02,0x02,0x00,0x00,0x00 };
>  static const uint8_t mxf_encrypted_triplet_key[]           = { 0x06,0x0e,0x2b,0x34,0x02,0x04,0x01,0x07,0x0d,0x01,0x03,0x01,0x02,0x7e,0x01,0x00 };
> +static const uint8_t mxf_encrypted_triplet_smpte_key[]     = { 0x06,0x0e,0x2b,0x34,0x02,0x04,0x01,0x01,0x0d,0x01,0x03,0x01,0x02,0x7e,0x01,0x00 };
>  static const uint8_t mxf_encrypted_essence_container[]     = { 0x06,0x0e,0x2b,0x34,0x04,0x01,0x01,0x07,0x0d,0x01,0x03,0x01,0x02,0x0b,0x01,0x00 };
>  static const uint8_t mxf_sony_mpeg4_extradata[]            = { 0x06,0x0e,0x2b,0x34,0x04,0x01,0x01,0x01,0x0e,0x06,0x06,0x02,0x02,0x01,0x00,0x00 };
>  static const uint8_t mxf_ffv1_extradata[]                  = { 0x06,0x0e,0x2b,0x34,0x01,0x01,0x01,0x0e,0x04,0x01,0x06,0x0c,0x01,0x00,0x00,0x00 }; // FFV1InitializationMetadata
> @@ -3738,6 +3739,7 @@ static int mxf_read_header(AVFormatContext *s)
>          PRINT_KEY(s, "read header", klv.key);
>          av_log(s, AV_LOG_TRACE, "size %"PRIu64" offset %#"PRIx64"\n", klv.length, klv.offset);
>          if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key) ||
> +            IS_KLV_KEY(klv.key, mxf_encrypted_triplet_smpte_key) ||

Calling one UL "mxf_encrypted_triplet_key" and the other
"mxf_encrypted_triplet_smpte_key" is misleading IMHO.

The only difference is the version byte, which should be ignored in
most, if not all, SMPTE UL comparisons.

I would instead use mxf_match_uid(), which ignores the version byte,
to compare the UL keys.


>              IS_KLV_KEY(klv.key, mxf_essence_element_key) ||
>              IS_KLV_KEY(klv.key, mxf_canopus_essence_element_key) ||
>              IS_KLV_KEY(klv.key, mxf_avid_essence_element_key) ||
> @@ -3983,7 +3985,8 @@ static int mxf_read_packet(AVFormatContext *s, AVPacket *pkt)
>              pos = klv.next_klv - klv.length;
>              PRINT_KEY(s, "read packet", klv.key);
>              av_log(s, AV_LOG_TRACE, "size %"PRIu64" offset %#"PRIx64"\n", klv.length, klv.offset);
> -            if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key)) {
> +            if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key) ||
> +                IS_KLV_KEY(klv.key, mxf_encrypted_triplet_smpte_key)) {
>                  ret = mxf_decrypt_triplet(s, pkt, &klv);
>                  if (ret < 0) {
>                      av_log(s, AV_LOG_ERROR, "invalid encoded triplet\n");
> --
> 2.25.1
>
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