[FFmpeg-devel] [PATCH 3/5] avformat/mp3dec: allow enabling generic seek mode

[Clément Bœsch]

On Tue, Apr 21, 2015 at 09:33:52PM +0200, wm4 wrote:
> "-usetoc 2" now invokes the generic seek and indexing mode. This mode
> skips data until the seek target is reached, and this is exact. It also
> makes gapless audio actually work if a seek past the start of the file
> is involved.
> ---
> Strange option value. On the other hand, it will be made default, so
> this option will generally be used only to select the "old" seek modes.
> But in general, libavformat should probably have something to switch
> between slow/accurate and fast/inaccurate seeking.
> ---
>  libavformat/mp3dec.c           | 12 +++++++++---
>  tests/fate/gapless.mak         |  5 +++--
>  tests/ref/fate/gapless-mp3     |  5 -----
>  tests/ref/fate/gapless-mp3-cbr |  5 +++++
>  4 files changed, 17 insertions(+), 10 deletions(-)
>  delete mode 100644 tests/ref/fate/gapless-mp3
>  create mode 100644 tests/ref/fate/gapless-mp3-cbr
> 
> diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c
> index 008cb23..8a4dfbd 100644
> --- a/libavformat/mp3dec.c
> +++ b/libavformat/mp3dec.c
> @@ -110,7 +110,7 @@ static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration
>  {
>      int i;
>      MP3DecContext *mp3 = s->priv_data;
> -    int fill_index = mp3->usetoc && duration > 0;
> +    int fill_index = mp3->usetoc == 1 && duration > 0;
>  
>      if (!filesize &&
>          !(filesize = avio_size(s->pb))) {
> @@ -336,6 +336,9 @@ static int mp3_read_header(AVFormatContext *s)
>      int ret;
>      int i;
>  
> +    if (mp3->usetoc < 0)
> +        mp3->usetoc = 0;
> +
>      st = avformat_new_stream(s, NULL);
>      if (!st)
>          return AVERROR(ENOMEM);
> @@ -432,8 +435,11 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
>      int64_t best_pos;
>      int best_score;
>  
> +    if (mp3->usetoc == 2)
> +        return -1; // generic index code
> +
>      if (   mp3->is_cbr
> -        && (mp3->usetoc <= 0 || !mp3->xing_toc)
> +        && (mp3->usetoc == 0 || !mp3->xing_toc)
>          && st->duration > 0
>          && mp3->header_filesize > s->internal->data_offset
>          && mp3->frames) {
> @@ -498,7 +504,7 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
>  }
>  
>  static const AVOption options[] = {
> -    { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, AV_OPT_FLAG_DECODING_PARAM},
> +    { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 2, AV_OPT_FLAG_DECODING_PARAM},

Can you use AV_OPT_TYPE_CONST for the different special values?

(and document it)

[...]

-- 
Clément B.
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