Re: [FFmpeg-devel] [PATCH v2 1/3] avformat/imfdec: use CPL start timecode if available

[Pierre-Anthony Lemieux <pal@sandflow.com>]

Hi Zane et al.,

Quick ping on the revised patchset below.

It addresses https://trac.ffmpeg.org/ticket/9842.

Best,

-- Pierre

On Sun, Oct 2, 2022 at 9:28 AM <pal@sandflow.com> wrote:
>
> From: Pierre-Anthony Lemieux <pal@palemieux.com>
>
> The IMF CPL contains an optional timecode start address. This patch reads the
> latter, if present, into the context's timecode metadata parameter.
> This addresses https://trac.ffmpeg.org/ticket/9842.
>
> ---
>  libavformat/imf.h     |   2 +
>  libavformat/imf_cpl.c | 106 ++++++++++++++++++++++++++++++++++++++++++
>  libavformat/imfdec.c  |  11 +++++
>  3 files changed, 119 insertions(+)
>
> diff --git a/libavformat/imf.h b/libavformat/imf.h
> index 4271cd9582..70ed007312 100644
> --- a/libavformat/imf.h
> +++ b/libavformat/imf.h
> @@ -59,6 +59,7 @@
>  #include "libavformat/avio.h"
>  #include "libavutil/rational.h"
>  #include "libavutil/uuid.h"
> +#include "libavutil/timecode.h"
>  #include <libxml/tree.h>
>
>  /**
> @@ -130,6 +131,7 @@ typedef struct FFIMFCPL {
>      AVUUID id_uuid;                               /**< CompositionPlaylist/Id element */
>      xmlChar *content_title_utf8;                     /**< CompositionPlaylist/ContentTitle element */
>      AVRational edit_rate;                            /**< CompositionPlaylist/EditRate element */
> +    AVTimecode *tc;                                  /**< CompositionPlaylist/CompositionTimecode element */
>      FFIMFMarkerVirtualTrack *main_markers_track;     /**< Main Marker Virtual Track */
>      FFIMFTrackFileVirtualTrack *main_image_2d_track; /**< Main Image Virtual Track */
>      uint32_t main_audio_track_count;                 /**< Number of Main Audio Virtual Tracks */
> diff --git a/libavformat/imf_cpl.c b/libavformat/imf_cpl.c
> index 474db6b7f5..183e6dd84e 100644
> --- a/libavformat/imf_cpl.c
> +++ b/libavformat/imf_cpl.c
> @@ -116,6 +116,22 @@ int ff_imf_xml_read_uint32(xmlNodePtr element, uint32_t *number)
>      return ret;
>  }
>
> +static int ff_imf_xml_read_boolean(xmlNodePtr element, int *value)
> +{
> +    int ret = 0;
> +
> +    xmlChar *element_text = xmlNodeListGetString(element->doc, element->xmlChildrenNode, 1);
> +    if (xmlStrcmp(element_text, "true") == 0 || xmlStrcmp(element_text, "1") == 0)
> +        *value = 1;
> +    else if (xmlStrcmp(element_text, "false") == 0 || xmlStrcmp(element_text, "0") == 0)
> +        *value = 0;
> +    else
> +        ret = 1;
> +    xmlFree(element_text);
> +
> +    return ret;
> +}
> +
>  static void imf_base_virtual_track_init(FFIMFBaseVirtualTrack *track)
>  {
>      memset(track->id_uuid, 0, sizeof(track->id_uuid));
> @@ -179,6 +195,90 @@ static int fill_content_title(xmlNodePtr cpl_element, FFIMFCPL *cpl)
>      return 0;
>  }
>
> +static int digit_to_int(char digit)
> +{
> +    if (digit >= '0' && digit <= '9')
> +        return digit - '0';
> +    return -1;
> +}
> +
> +/**
> + * Parses a string that conform to the TimecodeType used in IMF CPL and defined
> + * in SMPTE ST 2067-3.
> + * @param[in] s string to parse
> + * @param[out] tc_comps pointer to an array of 4 integers where the parsed HH,
> + *                      MM, SS and FF fields of the timecode are returned.
> + * @return 0 on success, < 0 AVERROR code on error.
> + */
> +static int parse_cpl_tc_type(const char *s, int *tc_comps)
> +{
> +    if (av_strnlen(s, 11) != 11)
> +        return AVERROR(EINVAL);
> +
> +    for (int i = 0; i < 4; i++) {
> +        int hi;
> +        int lo;
> +
> +        hi = digit_to_int(s[i * 3]);
> +        lo = digit_to_int(s[i * 3 + 1]);
> +
> +        if (hi == -1 || lo == -1)
> +            return AVERROR(EINVAL);
> +
> +        tc_comps[i] = 10 * hi + lo;
> +    }
> +
> +    return 0;
> +}
> +
> +static int fill_timecode(xmlNodePtr cpl_element, FFIMFCPL *cpl)
> +{
> +    xmlNodePtr tc_element = NULL;
> +    xmlNodePtr element = NULL;
> +    xmlChar *tc_str = NULL;
> +    int df = 0;
> +    int comps[4];
> +    int ret = 0;
> +
> +    tc_element = ff_imf_xml_get_child_element_by_name(cpl_element, "CompositionTimecode");
> +    if (!tc_element)
> +       return 0;
> +
> +    element = ff_imf_xml_get_child_element_by_name(tc_element, "TimecodeDropFrame");
> +    if (!element) {
> +        av_log(NULL, AV_LOG_ERROR, "CompositionTimecode element is missing\
> +                                    a TimecodeDropFrame child element\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (ff_imf_xml_read_boolean(element, &df)) {
> +        av_log(NULL, AV_LOG_ERROR, "TimecodeDropFrame element is invalid\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +    element = ff_imf_xml_get_child_element_by_name(tc_element, "TimecodeStartAddress");
> +    if (!element) {
> +        av_log(NULL, AV_LOG_ERROR, "CompositionTimecode element is missing\
> +                                    a TimecodeStartAddress child element\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    tc_str = xmlNodeListGetString(element->doc, element->xmlChildrenNode, 1);
> +    ret = parse_cpl_tc_type(tc_str, comps);
> +    xmlFree(tc_str);
> +    if (ret)
> +        return ret;
> +
> +    cpl->tc = av_malloc(sizeof(AVTimecode));
> +    if (!cpl->tc)
> +        return AVERROR(ENOMEM);
> +    ret = av_timecode_init_from_components(cpl->tc, cpl->edit_rate,
> +                                           df ? AV_TIMECODE_FLAG_DROPFRAME : 0,
> +                                           comps[0], comps[1], comps[2], comps[3],
> +                                           NULL);
> +
> +    return ret;
> +}
> +
>  static int fill_edit_rate(xmlNodePtr cpl_element, FFIMFCPL *cpl)
>  {
>      xmlNodePtr element = NULL;
> @@ -682,6 +782,8 @@ int ff_imf_parse_cpl_from_xml_dom(xmlDocPtr doc, FFIMFCPL **cpl)
>          goto cleanup;
>      if ((ret = fill_edit_rate(cpl_element, *cpl)))
>          goto cleanup;
> +    if ((ret = fill_timecode(cpl_element, *cpl)))
> +        goto cleanup;
>      if ((ret = fill_virtual_tracks(cpl_element, *cpl)))
>          goto cleanup;
>
> @@ -731,6 +833,7 @@ static void imf_cpl_init(FFIMFCPL *cpl)
>      av_uuid_nil(cpl->id_uuid);
>      cpl->content_title_utf8 = NULL;
>      cpl->edit_rate = av_make_q(0, 1);
> +    cpl->tc = NULL;
>      cpl->main_markers_track = NULL;
>      cpl->main_image_2d_track = NULL;
>      cpl->main_audio_track_count = 0;
> @@ -753,6 +856,9 @@ void ff_imf_cpl_free(FFIMFCPL *cpl)
>      if (!cpl)
>          return;
>
> +    if (cpl->tc)
> +        av_freep(&cpl->tc);
> +
>      xmlFree(cpl->content_title_utf8);
>
>      imf_marker_virtual_track_free(cpl->main_markers_track);
> diff --git a/libavformat/imfdec.c b/libavformat/imfdec.c
> index 4e60dcc4ba..03de9ce151 100644
> --- a/libavformat/imfdec.c
> +++ b/libavformat/imfdec.c
> @@ -627,6 +627,8 @@ static int imf_read_header(AVFormatContext *s)
>      IMFContext *c = s->priv_data;
>      char *asset_map_path;
>      char *tmp_str;
> +    AVDictionaryEntry* tcr;
> +    char tc_buf[AV_TIMECODE_STR_SIZE];
>      int ret = 0;
>
>      c->interrupt_callback = &s->interrupt_callback;
> @@ -646,6 +648,15 @@ static int imf_read_header(AVFormatContext *s)
>      if ((ret = ff_imf_parse_cpl(s->pb, &c->cpl)) < 0)
>          return ret;
>
> +    tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
> +    if (!tcr && c->cpl->tc) {
> +        ret = av_dict_set(&s->metadata, "timecode",
> +                          av_timecode_make_string(c->cpl->tc, tc_buf, 0), 0);
> +        if (ret)
> +            return ret;
> +        av_log(s, AV_LOG_INFO, "Setting timecode to IMF CPL timecode %s\n", tc_buf);
> +    }
> +
>      av_log(s,
>             AV_LOG_DEBUG,
>             "parsed IMF CPL: " AV_PRI_URN_UUID "\n",
> --
> 2.25.1
>
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