Hello
2018-01-10 11:33 GMT+01:00 Moritz Barsnick <barsn...@gmx.net>:
> On Wed, Jan 10, 2018 at 08:58:05 +0100, dmitry.gumen...@gmail.com wrote:
>
>> +@table @option
>> +@item d
>> +Dimensions @code{WxH}.
>> +@code{W} - number of data values in json, values will be scaled according
>> to @code{H}.
>> +The default value is @var{640x480}
>> +
>> +@item s
>> +Samples count per value per channel
>
> In most other filters/filtersources, s+size is used for dimensions,
> d+duration for time, and n for an amount/number of frames/samples or
> so. Might be a good idea to align with this. And use aliases (i.e.
> implement both "s" and "size").
>
>> +static const AVOption dumpwave_options[] = {
>> + { "d", "set width and height", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str
>> = "640x480"}, 0, 0, FLAGS },
>> + { "s", "set number of samples per value per channel", OFFSET(s),
>> AV_OPT_TYPE_INT64, {.i64 = 0}, 0, INT64_MAX, FLAGS },
>> + { "json", "set json dump file", OFFSET(json), AV_OPT_TYPE_STRING, {
>> .str = NULL }, 0, 0, FLAGS },
>> + { NULL }
> [...]
>> +static av_cold int init(AVFilterContext *ctx)
>> +{
>> + DumpWaveContext *dumpwave = ctx->priv;
>> + if(!dumpwave->s) {
>> + dumpwave->is_disabled = 1;
>> + av_log(ctx, AV_LOG_ERROR, "Invalid samples per value config\n");
>> + }
>> + return 0;
>
> I don't like the idea of having to provide the "s" parameter. Is there
> really no useful default?
>
> And now, if s=0, what does the filter do? Just sit around? Couldn't it
> fail instead?
>
> Apart from that:
> "if (" is the bracket style ffmpeg uses.
>
>> + if (dumpwave->json && !(dump_fp = av_fopen_utf8(dumpwave->json,
>> "w")))
>> + av_log(ctx, AV_LOG_WARNING, "Flushing dump failed\n");
>
> I would appreciate evaluation of errno and printing the appropriate
> string (using av_strerror(), I believe).
>
>> + switch (inlink->format) {
>> + case AV_SAMPLE_FMT_DBLP:
>
> As Kyle hinted: Can this not force a conversion (implicit insertion of
> aformat filter) to e.g. double by only supporting this format, and
> reducing this switch to one or two cases? (The filter's output isn't
> really meant for transparent reuse anyway? af_volumedetect e.g. also
> supports only one, meaning its output can be a different format than
> its input.) It's also really hard to go through and later to maintain.
> It the big switch/case remains, one or two code macros would be
> appropriate.
I checked solution used in volumedetect and couldn't find a way to
read across formats.
How would you implement such macros? Since version 3.2 astats filter
uses same approach for reading different formats and as far as I know
macros harder to debug
>> + for (i = 0; i < buf->nb_samples; i++) {
>> + for (c = 0; c < channels; c++, src++)
>> + calc_db_rms(dumpwave, *src);
>> + }}
>
> I believe the curly brackets need to be placed differently.
>
>> + .description = NULL_IF_CONFIG_SMALL("Dumps RMS amplitude to JSON
>> file"),
>
> Imperative, i.e. "Dump RMS ...".
>
>> +FATE_AFILTER-$(call FILTERDEMDEC, DUMPWAVE, WAV, PCM_S16LE) +=
>> fate-filter-dumpwave
>> +fate-filter-dumpwave: SRC = $(TARGET_PATH)/tests/data/asynth-44100-2.wav
>> +fate-filter-dumpwave: CMD = ffmpeg -i $(SRC) -af
>> dumpwave=d=1800x140:s=147:json=$(TARGET_PATH)/tests/data/fate/filter-dumpwave.out
>> -f null - && cat $(TARGET_PATH)/tests/data/fate/filter-dumpwave.out
>> +
>
> If you need to implement all formats, you might want to test them all.
> Just a thought.
>
> Moritz
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