On Mon, 22 Jan 2018 15:48:07 -0800
Richard Shaffer <rshaf...@tunein.com> wrote:
> On Mon, Jan 22, 2018 at 3:18 PM, wm4 <nfx...@googlemail.com> wrote:
>
> > On Wed, 17 Jan 2018 16:34:39 -0800
> > rshaf...@tunein.com wrote:
> >
> > > From: Richard Shaffer <rshaf...@tunein.com>
> > >
> > > Enables getting access to ID3 PRIV tags from the command-line or
> > metadata API
> > > when demuxing. The PRIV owner is stored as the metadata key prepended
> > with
> > > "id3v2_priv.", and the data is stored as the metadata value. As PRIV
> > tags may
> > > contain arbitrary data, non-printable characters, including NULL bytes,
> > are
> > > escaped as \xXX.
> > >
> > > Similarly, any metadata tags that begin with "id3v2_priv." are inserted
> > as ID3
> > > PRIV tags into the output (assuming the format supports ID3). \xXX
> > sequences in
> > > the value are un-escaped to their byte value.
> > > ---
> > >
> > > Sorry. One more update. I realized there was a possibility of reading
> > past the
> > > end of input in id3v2_put_priv, so I added a fix.
> > >
> > > -Richard
> > >
> > > libavformat/id3v2.c | 48 +++++++++++++++++++++++++++++++++++++
> > > libavformat/id3v2.h | 15 ++++++++++++
> > > libavformat/id3v2enc.c | 64 ++++++++++++++++++++++++++++++
> > ++++++++++++++++++++
> > > libavformat/utils.c | 2 ++
> > > 4 files changed, 129 insertions(+)
> > >
> > > diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
> > > index 6c216ba7a2..e46174d7c7 100644
> > > --- a/libavformat/id3v2.c
> > > +++ b/libavformat/id3v2.c
> > > @@ -33,6 +33,7 @@
> > > #endif
> > >
> > > #include "libavutil/avstring.h"
> > > +#include "libavutil/bprint.h"
> > > #include "libavutil/dict.h"
> > > #include "libavutil/intreadwrite.h"
> > > #include "avio_internal.h"
> > > @@ -1224,3 +1225,50 @@ end:
> > > av_freep(&chapters);
> > > return ret;
> > > }
> > > +
> > > +int ff_id3v2_parse_priv_dict(AVDictionary **metadata, ID3v2ExtraMeta
> > **extra_meta)
> > > +{
> > > + ID3v2ExtraMeta *cur;
> > > + int dict_flags = AV_DICT_DONT_OVERWRITE | AV_DICT_DONT_STRDUP_KEY |
> > AV_DICT_DONT_STRDUP_VAL;
> > > +
> > > + for (cur = *extra_meta; cur; cur = cur->next) {
> > > + if (!strcmp(cur->tag, "PRIV")) {
> > > + ID3v2ExtraMetaPRIV *priv = cur->data;
> > > + AVBPrint bprint;
> > > + char * escaped, * key;
> > > + int i, ret;
> > > +
> > > + if ((key = av_asprintf(ID3v2_PRIV_METADATA_PREFIX "%s",
> > priv->owner)) == NULL) {
> > > + return AVERROR(ENOMEM);
> > > + }
> > > +
> > > + av_bprint_init(&bprint, priv->datasize + 1,
> > AV_BPRINT_SIZE_UNLIMITED);
> > > +
> > > + for (i = 0; i < priv->datasize; i++) {
> > > + if (priv->data[i] < 32 || priv->data[i] > 126 ||
> > priv->data[i] == '\\') {
> > > + av_bprintf(&bprint, "\\x%02x", priv->data[i]);
> > > + } else {
> > > + av_bprint_chars(&bprint, priv->data[i], 1);
> > > + }
> > > + }
> > > +
> > > + if ((ret = av_bprint_finalize(&bprint, &escaped)) < 0) {
> > > + av_free(key);
> > > + return ret;
> > > + }
> > > +
> > > + if ((ret = av_dict_set(metadata, key, escaped, dict_flags))
> > < 0) {
> > > + av_free(key);
> > > + av_free(escaped);
> > > + return ret;
> > > + }
> > > + }
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +int ff_id3v2_parse_priv(AVFormatContext *s, ID3v2ExtraMeta
> > **extra_meta)
> > > +{
> > > + return ff_id3v2_parse_priv_dict(&s->metadata, extra_meta);
> > > +}
> > > \ No newline at end of file
> > > diff --git a/libavformat/id3v2.h b/libavformat/id3v2.h
> > > index 5e64ead096..9de0bee374 100644
> > > --- a/libavformat/id3v2.h
> > > +++ b/libavformat/id3v2.h
> > > @@ -39,6 +39,8 @@
> > > #define ID3v2_FLAG_ENCRYPTION 0x0004
> > > #define ID3v2_FLAG_COMPRESSION 0x0008
> > >
> > > +#define ID3v2_PRIV_METADATA_PREFIX "id3v2_priv."
> > > +
> > > enum ID3v2Encoding {
> > > ID3v2_ENCODING_ISO8859 = 0,
> > > ID3v2_ENCODING_UTF16BOM = 1,
> > > @@ -167,6 +169,19 @@ int ff_id3v2_parse_apic(AVFormatContext *s,
> > ID3v2ExtraMeta **extra_meta);
> > > */
> > > int ff_id3v2_parse_chapters(AVFormatContext *s, ID3v2ExtraMeta
> > **extra_meta);
> > >
> > > +/**
> > > + * Parse PRIV tags into a dictionary. The PRIV owner is the metadata
> > key. The
> > > + * PRIV data is the value, with non-printable characters escaped.
> > > + */
> > > +int ff_id3v2_parse_priv_dict(AVDictionary **d, ID3v2ExtraMeta
> > **extra_meta);
> > > +
> > > +/**
> > > + * Add metadata for all PRIV tags in the ID3v2 header. The PRIV owner
> > is the
> > > + * metadata key. The PRIV data is the value, with non-printable
> > characters
> > > + * escaped.
> > > + */
> > > +int ff_id3v2_parse_priv(AVFormatContext *s, ID3v2ExtraMeta
> > **extra_meta);
> > > +
> > > extern const AVMetadataConv ff_id3v2_34_metadata_conv[];
> > > extern const AVMetadataConv ff_id3v2_4_metadata_conv[];
> > >
> > > diff --git a/libavformat/id3v2enc.c b/libavformat/id3v2enc.c
> > > index 14de76ac06..d5e358c8b6 100644
> > > --- a/libavformat/id3v2enc.c
> > > +++ b/libavformat/id3v2enc.c
> > > @@ -96,6 +96,63 @@ static int id3v2_put_ttag(ID3v2EncContext *id3,
> > AVIOContext *avioc, const char *
> > > return len + ID3v2_HEADER_SIZE;
> > > }
> > >
> > > +/**
> > > + * Write a priv frame with owner and data. 'key' is the owner prepended
> > with
> > > + * ID3v2_PRIV_METADATA_PREFIX. 'data' is provided as a string. Any \xXX
> > > + * (where 'X' is a valid hex digit) will be unescaped to the byte value.
> > > + */
> > > +static int id3v2_put_priv(ID3v2EncContext *id3, AVIOContext *avioc,
> > const char *key, const char *data)
> > > +{
> > > + int len;
> > > + uint8_t *pb;
> > > + AVIOContext *dyn_buf;
> > > +
> > > + if (!av_strstart(key, ID3v2_PRIV_METADATA_PREFIX, &key)) {
> > > + return 0;
> > > + }
> > > +
> > > + if (avio_open_dyn_buf(&dyn_buf) < 0)
> > > + return AVERROR(ENOMEM);
> > > +
> > > + // owner + null byte.
> > > + avio_write(dyn_buf, key, strlen(key) + 1);
> > > +
> > > + while (*data) {
> > > + if (av_strstart(data, "\\x", &data)) {
> > > + if (data[0] && data[1] && av_isxdigit(data[0]) &&
> > av_isxdigit(data[1])) {
> > > + char digits[] = {data[0], data[1], 0};
> > > + avio_w8(dyn_buf, strtol(digits, NULL, 16));
> > > + } else {
> > > + // '\x' wasn't followed by two hex digits. Just write
> > out
> > > + // whatever the 2-4 characters were.
> > > + avio_write(dyn_buf, "\\x", 2);
> > > + if (data[0]) {
> > > + avio_w8(dyn_buf, data[0]);
> > > + if (data[1])
> > > + avio_w8(dyn_buf, data[1]);
> > > + }
> >
> > Wouldn't this be slightly nicer if you only wrote the "\\x" here, and
> > moved the "data += 2;" to the case when the digits were valid?
> >
> > Though personally I'd probably prefer if it just errored out on invalid
> > input, but dunno.
> >
>
> Not a bad idea to just error out, I guess. Probably better than silently
> writing data that could be a bug. Would this be better?
>
> if (av_strstart(data, "\\x", &data)) {
> if (data[0] && data[1] && av_isxdigit(data[0]) &&
> av_isxdigit(data[1])) {
> char digits[] = {data[0], data[1], 0};
> avio_w8(dyn_buf, strtol(digits, NULL, 16));
> data += 2;
> } else {
> ffio_free_dyn_buf(&dyn_buf);
> av_log(avioc, AV_LOG_ERROR, "Invalid escape \\x%.2s in
> metadata tag '%s'.\n", data, key);
> return AVERROR(EINVAL);;
> }
> } else {
> avio_write(dyn_buf, data++, 1);
> }
Yeah, I'd feel slightly better about this.
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