On 03/25/2011 07:06 PM, Anton Khirnov wrote:
> From: Kharkov Alexander <[email protected]>
>
Shorter lines might be welcome,
> + * 'keyframes' metatag is not part of standart it is just
> + * convention to use such kind of metatag information for
indexing, but
> + * nobody can prevent end user to create FLV file with keyframes
metadata
> + * with it's own structure, for own purposed, in that case we just
> + * ignore such data. Two sizes compared because they packet in
two different
> + * arrays in metadata, that is why they can have different sizes
in case of bug
> + * in tool which insert metatags for example.
> + * Strructure is following, it allows to have it inconsistent:
> + * keyframes:
> + * times (array):
> + * time0 (num)
> + * time1 (num)
> + * time2 (num)
> + * filepositions (array)
> + * position0 (num)
> + * position1 (num)
Should be part of the commit message, imho the memory allocation failure
should be addressed in a different way, beside that seems more or less ok.
lu
> ---
> libavformat/flvdec.c | 78
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 78 insertions(+), 0 deletions(-)
>
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index 2152f7d..0a93fc7 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -31,6 +31,10 @@
> #include "avio_internal.h"
> #include "flv.h"
>
> +#define KEYFRAMES_TAG "keyframes"
> +#define KEYFRAMES_TIMESTAMP_TAG "times"
> +#define KEYFRAMES_BYTEOFFSET_TAG "filepositions"
> +
> typedef struct {
> int wrong_dts; ///< wrong dts due to negative cts
> } FLVContext;
> @@ -125,6 +129,77 @@ static int amf_get_string(AVIOContext *ioc, char
> *buffer, int buffsize) {
> return length;
> }
>
> +static void parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
> AVStream *vstream, int64_t max_pos) {
> + unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
> + double num_val;
> + char str_val[256];
> + int64_t *times = NULL;
> + int64_t *filepositions = NULL;
> +
> + while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val,
> sizeof(str_val)) > 0) {
> + int64_t* current_array;
> +
> + // Expect array object in context
> + if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
> + break;
> +
> + arraylen = avio_rb32(ioc);
> + /*
> + * Expect only 'times' or 'filepositions' sub-arrays in other case
> refuse to use such metadata
> + * for indexing
> + */
> + if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val)) {
> + if (times ||
> + !(times = av_mallocz(sizeof(*times) * arraylen)))
> + break;
> + timeslen = arraylen;
> + current_array = times;
> + } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val)) {
> + if (filepositions ||
> + !(filepositions = av_mallocz(sizeof(*filepositions) *
> arraylen)))
> + break;
> + fileposlen = arraylen;
> + current_array = filepositions;
> + } else // unexpected metatag inside keyframes, will not use such
> metadata for indexing
> + break;
> +
> + for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
> + if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
> + goto finish;
> + num_val = av_int2dbl(avio_rb64(ioc));
> + current_array[i] = num_val;
> + }
> + }
> +
> + /*
> + * One more sanity check.
> + * 'keyframes' metatag is not part of standart it is just
> + * convention to use such kind of metatag information for indexing, but
> + * nobody can prevent end user to create FLV file with keyframes metadata
> + * with it's own structure, for own purposed, in that case we just
> + * ignore such data. Two sizes compared because they packet in two
> different
> + * arrays in metadata, that is why they can have different sizes in case
> of bug
> + * in tool which insert metatags for example.
> + * Strructure is following, it allows to have it inconsistent:
> + * keyframes:
> + * times (array):
> + * time0 (num)
> + * time1 (num)
> + * time2 (num)
> + * filepositions (array)
> + * position0 (num)
> + * position1 (num)
> + */
> + if(timeslen == fileposlen)
> + for(i = 0; i < arraylen; i++)
> + av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0,
> 0, AVINDEX_KEYFRAME);
> +
> +finish:
> + av_freep(×);
> + av_freep(&filepositions);
> + avio_seek(ioc, max_pos, SEEK_SET);
> +}
> +
> static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream
> *vstream, const char *key, int64_t max_pos, int depth) {
> AVCodecContext *acodec, *vcodec;
> AVIOContext *ioc;
> @@ -149,6 +224,9 @@ static int amf_parse_object(AVFormatContext *s, AVStream
> *astream, AVStream *vst
> case AMF_DATA_TYPE_OBJECT: {
> unsigned int keylen;
>
> + if (!strcmp(KEYFRAMES_TAG, key) && depth == 1)
> + parse_keyframes_index(s, ioc, vstream, max_pos);
> +
> while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc)))
> {
> avio_skip(ioc, keylen); //skip key string
> if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1)
> < 0)
--
Luca Barbato
Gentoo/linux
http://dev.gentoo.org/~lu_zero
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