[FFmpeg-devel] [PATCH+RFC] AVFrame for audio
Michael Niedermayer
michaelni
Mon Nov 1 14:14:42 CET 2010
On Sat, Oct 30, 2010 at 08:06:42AM -0400, Justin Ruggles wrote:
> Michael Niedermayer wrote:
>
> > On Thu, Oct 28, 2010 at 06:58:11PM -0400, Justin Ruggles wrote:
> >> Michael Niedermayer wrote:
> >>
> >>> On Wed, Oct 27, 2010 at 10:13:10PM -0400, Justin Ruggles wrote:
> >>>> Michael Niedermayer wrote:
> >>>>
> >>>>> On Tue, Oct 26, 2010 at 09:31:13PM -0400, Justin Ruggles wrote:
> >>>>>> Michael Niedermayer wrote:
> >>>>>>
> >>>>>>> On Sun, Oct 17, 2010 at 05:22:54PM -0400, Justin Ruggles wrote:
> >>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>
> >>>>>>>>> On Sat, Oct 16, 2010 at 04:12:26PM -0400, Justin Ruggles wrote:
> >>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>
> >>>>>>>>>>> On Fri, Oct 15, 2010 at 06:35:01PM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>> Justin Ruggles wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> On Wed, Oct 13, 2010 at 07:52:12PM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> On Wed, Oct 06, 2010 at 11:05:26AM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> On Tue, Oct 05, 2010 at 04:55:12PM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> On Wed, Sep 29, 2010 at 09:20:04PM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>>>>>>>>>>> Hi,
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>> Peter Ross wrote:
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>> On Thu, Sep 02, 2010 at 07:11:37PM -0400, Justin Ruggles wrote:
> >>>>>>>>>>>>>>>>>>>>>>> Hi,
> >>>>>>>>>>>>>>>> [...]
> >>>>>>>>>>>>>>>>>>>> [...]
> >>>>>>>>>>>>>>>>>>>>> @@ -644,29 +677,49 @@
> >>>>>>>>>>>>>>>>>>>>> }
> >>>>>>>>>>>>>>>>>>>>> #endif
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>> +#if LIBAVCODEC_VERSION_MAJOR < 53
> >>>>>>>>>>>>>>>>>>>>> int attribute_align_arg avcodec_decode_audio3(AVCodecContext *avctx, int16_t *samples,
> >>>>>>>>>>>>>>>>>>>>> int *frame_size_ptr,
> >>>>>>>>>>>>>>>>>>>>> AVPacket *avpkt)
> >>>>>>>>>>>>>>>>>>>>> {
> >>>>>>>>>>>>>>>>>>>>> + AVFrame frame;
> >>>>>>>>>>>>>>>>>>>>> + int ret, got_frame = 0;
> >>>>>>>>>>>>>>>>>>>>> +
> >>>>>>>>>>>>>>>>>>>>> + avcodec_get_frame_defaults(&frame);
> >>>>>>>>>>>>>>>>>>>>> +
> >>>>>>>>>>>>>>>>>>>>> + ret = avcodec_decode_audio4(avctx, &frame, &got_frame, avpkt);
> >>>>>>>>>>>>>>>>>>>>> +
> >>>>>>>>>>>>>>>>>>>>> + if (ret >= 0 && got_frame) {
> >>>>>>>>>>>>>>>>>>>>> + *frame_size_ptr = frame.nb_samples * avctx->channels *
> >>>>>>>>>>>>>>>>>>>>> + (av_get_bits_per_sample_format(avctx->sample_fmt) / 8);
> >>>>>>>>>>>>>>>>>>>>> +
> >>>>>>>>>>>>>>>>>>>>> + /* ensure data will fit in the output buffer */
> >>>>>>>>>>>>>>>>>>>>> + if (*frame_size_ptr > AVCODEC_MAX_AUDIO_FRAME_SIZE) {
> >>>>>>>>>>>>>>>>>>>>> + av_log(avctx, AV_LOG_WARNING, "avcodec_decode_audio3 samples "
> >>>>>>>>>>>>>>>>>>>>> + "truncated to AVCODEC_MAX_AUDIO_FRAME_SIZE\n");
> >>>>>>>>>>>>>>>>>>>>> + *frame_size_ptr = AVCODEC_MAX_AUDIO_FRAME_SIZE;
> >>>>>>>>>>>>>>>>>>>>> + }
> >>>>>>>>>>>>>>>>>>>>> +
> >>>>>>>>>>>>>>>>>>>>> + memcpy(samples, frame.data[0], *frame_size_ptr);
> >>>>>>>>>>>>>>>>>>>> the default get_buffer() should return the appropriate
> >>>>>>>>>>>>>>>>>>>> buffer for this case.
> >>>>>>>>>>>>>>>>>>> I'm sorry, I don't understand your comment.
> >>>>>>>>>>>>>>>>>> i mean (non functional psseudocode below to explain the idea)
> >>>>>>>>>>>>>>>>>> avcodec_decode_audio3(){
> >>>>>>>>>>>>>>>>>> avctx->foobar= samples;
> >>>>>>>>>>>>>>>>>> ret = avcodec_decode_audio4(avctx, &frame, &got_frame, avpkt);
> >>>>>>>>>>>>>>>>>> ...
> >>>>>>>>>>>>>>>>>> assert(samples == frame.data[0]);
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> -----
> >>>>>>>>>>>>>>>>>> default_get_buffer(){
> >>>>>>>>>>>>>>>>>> if(avctx->foobar)
> >>>>>>>>>>>>>>>>>> return avctx->foobar;
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> (and yes this cannot work for all theoretical decoders)
> >>>>>>>>>>>>>>>>> I think I get it. So avctx->foobar would be an optional user-supplied
> >>>>>>>>>>>>>>>>> buffer (avctx->user_buffer?) that default_get_buffer() would return if
> >>>>>>>>>>>>>>>>> it is non-NULL, right?
> >>>>>>>>>>>>>>>> yes
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> The problem I see is this:
> >>>>>>>>>>>>>>>>> avcodec_decode_audio3() would use avcodec_decode_audio4().
> >>>>>>>>>>>>>>>>> avcodec_decode_audio4() allocates as large a buffer as is needed through
> >>>>>>>>>>>>>>>>> get_buffer(), but the avcodec_decode_audio3() API only requires the
> >>>>>>>>>>>>>>>>> user-supplied buffer to be AVCODEC_MAX_AUDIO_FRAME_SIZE. Couldn't this
> >>>>>>>>>>>>>>>>> lead to the decoder writing past the end of a user-supplied buffer if it
> >>>>>>>>>>>>>>>>> isn't large enough? I guess we could also add a field
> >>>>>>>>>>>>>>>>> avctx->user_buffer_size?
> >>>>>>>>>>>>>>>> yes, of course
> >>>>>>>>>>>>>>>> it was just a rough idea ...
> >>>>>>>>>>>>>>> I'm running into some questions trying to implement the rough idea. The
> >>>>>>>>>>>>>>> only way I can see this working smoothly is if avcodec_decode_audio3()
> >>>>>>>>>>>>>>> always sets get/release_buffer to default. Also, either all audio
> >>>>>>>>>>>>>>> decoders will have to support CODEC_CAP_DR1 (i.e. they always use
> >>>>>>>>>>>>>>> get/release_buffer) or there needs to be a fallback that will memcpy
> >>>>>>>>>>>>>>> into the user buffer if CODEC_CAP_DR1 is not supported.
> >>>>>>>>>>>>>> old API decoders surely dont need to copy with old API.
> >>>>>>>>>>>>>> old API decoders surely dont need to copy with new API if the api can provide
> >>>>>>>>>>>>>> a buffer to the decoder (this can be through function argument like its done
> >>>>>>>>>>>>>> currently)
> >>>>>>>>>>>>>> new API decoders surely dont need to copy with new API because otherwise the
> >>>>>>>>>>>>>> API sucks and needs more work
> >>>>>>>>>>>>>> whats left is new API decoders and used with old API and for this get_buffer()
> >>>>>>>>>>>>>> should return the user supplied buffer if its large enough and fail if its not
> >>>>>>>>>>>>>> large enough.
> >>>>>>>>>>>>>> The case where the user overrides get_buffer() and supplies a user specified
> >>>>>>>>>>>>>> buffer which its own code doesnt use is a case that id consider user error.
> >>>>>>>>>>>>> I think I might have been misinterpreting the API. For video decoders,
> >>>>>>>>>>>>> what does it mean as far as buffer allocation when CODEC_CAP_DR1 is not set?
> >>>>>>>>>>>> So I think I have this worked out and I don't see how we can avoid a
> >>>>>>>>>>>> memcpy with the old API when CODEC_CAP_DR1 is not set. There would be
> >>>>>>>>>>>> no other way to get the data into the correct output buffer.
> >>>>>>>>>>>>
> >>>>>>>>>>>> other questions:
> >>>>>>>>>>>>
> >>>>>>>>>>>> 1. Should AVCodecContext.user_buffer be supported for video decoders?
> >>>>>>>>>>> possible but this is seperate, lets not entangle this patch with too many
> >>>>>>>>>>> other changes
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>> If so, should it be user_buffer[4] and user_buffer_size[4]?
> >>>>>>>>>>> possible
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>> 2. avcodec_default_get_buffer() supports allocating multiple internal
> >>>>>>>>>>>> buffers. How should that be handled if the buffer is supplied by the
> >>>>>>>>>>>> user? Don't support multiple buffers? Use the user-supplied buffer
> >>>>>>>>>>>> just for the first one?
> >>>>>>>>>>> there are buffer hints (grep for hint in avcodec.h) that specify if a buffer
> >>>>>>>>>>> will be reused/read/preserved/blah
> >>>>>>>>>>> the user supplied buffer is likely just valid for this call and cannot be used
> >>>>>>>>>>> for some cases of the hints. For what remains using the buffer on the first
> >>>>>>>>>>> call only seems ok
> >>>>>>>>>> I think I've implemented it in a way that will work even when the
> >>>>>>>>>> various buffer hints are set. This implementation will not use memcpy
> >>>>>>>>>> in avcodec_decode_audio3() in the most common case of the decoder
> >>>>>>>>>> supporting CODEC_CAP_DR1, only needing 1 buffer, and not needing a
> >>>>>>>>>> buffer larger than AVCODEC_MAX_AUDIO_FRAME_SIZE.
> >>>>>>>>>>
> >>>>>>>>>> One thing I'm unsure of is whether to truncate output if it is too large
> >>>>>>>>>> for avcodec_decode_audio3() (which is done in this patch) or to return
> >>>>>>>>>> an error instead.
> >>>>>>>>> I think its better to tell the user straight through an error that there is a
> >>>>>>>>> problem instead of generating output that contains randomly truncated packets
> >>>>>>>> Ok. New patch.
> >>>>>>>>
> >>>>>>>> -Justin
> >>>>>>> [...]
> >>>>>>>> int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){
> >>>>>>>> int i;
> >>>>>>>> int w= s->width;
> >>>>>>>> int h= s->height;
> >>>>>>>> + int is_video = (s->codec_type == AVMEDIA_TYPE_VIDEO);
> >>>>>>>> InternalBuffer *buf;
> >>>>>>>> int *picture_number;
> >>>>>>>>
> >>>>>>>> @@ -235,7 +258,8 @@ int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){
> >>>>>>>> return -1;
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> - if(av_image_check_size(w, h, 0, s))
> >>>>>>>> + if(( is_video && av_image_check_size(w, h, 0, s)) ||
> >>>>>>>> + (!is_video && audio_check_size(s->channels, pic->nb_samples, s->sample_fmt)))
> >>>>>>>> return -1;
> >>>>>>>>
> >>>>>>>> if(s->internal_buffer==NULL){
> >>>>>>>> @@ -253,17 +277,30 @@ int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){
> >>>>>>>> picture_number= &(((InternalBuffer*)s->internal_buffer)[INTERNAL_BUFFER_SIZE]).last_pic_num; //FIXME ugly hack
> >>>>>>>> (*picture_number)++;
> >>>>>>>>
> >>>>>>>> - if(buf->base[0] && (buf->width != w || buf->height != h || buf->pix_fmt != s->pix_fmt)){
> >>>>>>>> + if (buf->base[0]) {
> >>>>>>>> + if (is_video && (buf->width != w || buf->height != h || buf->pix_fmt != s->pix_fmt)){
> >>>>>>>> for(i=0; i<4; i++){
> >>>>>>>> av_freep(&buf->base[i]);
> >>>>>>>> buf->data[i]= NULL;
> >>>>>>>> }
> >>>>>>>> + } else if (!is_video && (buf->channels != s->channels ||
> >>>>>>>> + buf->nb_samples != pic->nb_samples ||
> >>>>>>>> + buf->sample_fmt != s->sample_fmt)) {
> >>>>>>>> + if (buf->base[0] == s->user_buffer) {
> >>>>>>>> + s->user_buffer_in_use = 0;
> >>>>>>>> + buf->base[0] = NULL;
> >>>>>>>> + } else {
> >>>>>>>> + av_freep(&buf->base[0]);
> >>>>>>>> + }
> >>>>>>>> + buf->data[0] = NULL;
> >>>>>>>> + }
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> if(buf->base[0]){
> >>>>>>>> pic->age= *picture_number - buf->last_pic_num;
> >>>>>>>> buf->last_pic_num= *picture_number;
> >>>>>>>> }else{
> >>>>>>>> + if (is_video) {
> >>>>>>>> int h_chroma_shift, v_chroma_shift;
> >>>>>>>> int size[4] = {0};
> >>>>>>>> int tmpsize;
> >>>>>>>> @@ -327,6 +364,28 @@ int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){
> >>>>>>>> buf->height = s->height;
> >>>>>>>> buf->pix_fmt= s->pix_fmt;
> >>>>>>>> pic->age= 256*256*256*64;
> >>>>>>>> + } else { /* audio */
> >>>>>>>> + int buf_size;
> >>>>>>>> +
> >>>>>>>> + buf->last_pic_num = -256*256*256*64;
> >>>>>>>> +
> >>>>>>>> + buf_size = pic->nb_samples * s->channels *
> >>>>>>>> + (av_get_bits_per_sample_format(s->sample_fmt) / 8);
> >>>>>>>> +
> >>>>>>>> + if (s->user_buffer && !s->user_buffer_in_use && s->user_buffer_size >= buf_size) {
> >>>>>>>> + buf->base[0] = s->user_buffer;
> >>>>>>>> + s->user_buffer_in_use = 1;
> >>>>>>>> + } else {
> >>>>>>>> + buf->base[0] = av_mallocz(buf_size);
> >>>>>>>> + if (!buf->base[0])
> >>>>>>>> + return AVERROR(ENOMEM);
> >>>>>>>> + }
> >>>>>>>> +
> >>>>>>>> + buf->data[0] = buf->base[0];
> >>>>>>>> + buf->channels = s->channels;
> >>>>>>>> + buf->nb_samples = pic->nb_samples;
> >>>>>>>> + buf->sample_fmt = s->sample_fmt;
> >>>>>>>> + }
> >>>>>>>> }
> >>>>>>>> pic->type= FF_BUFFER_TYPE_INTERNAL;
> >>>>>>>>
> >>>>>>>> @@ -360,9 +419,15 @@ void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){
> >>>>>>>> }
> >>>>>>>> assert(i < s->internal_buffer_count);
> >>>>>>>> s->internal_buffer_count--;
> >>>>>>>> + if (buf->base[0] == s->user_buffer) {
> >>>>>>>> + assert(s->user_buffer_in_use);
> >>>>>>>> + s->user_buffer_in_use = 0;
> >>>>>>>> + buf->base[0] = NULL;
> >>>>>>>> + } else {
> >>>>>>>> last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
> >>>>>>>>
> >>>>>>>> FFSWAP(InternalBuffer, *buf, *last);
> >>>>>>>> + }
> >>>>>>>>
> >>>>>>>> for(i=0; i<4; i++){
> >>>>>>>> pic->data[i]=NULL;
> >>>>>>> i dont see how this could work
> >>>>>>> the buffer used and returned by the previous decode() is put in a que by the
> >>>>>>> user app and user_buffer is set to a new buffer.
> >>>>>>> also you appear to end up calling av_free()
> >>>>>>> on user supplied buffers
> >>>>>> Well, I meant to disallow that, but the documentation I put just says
> >>>>>> the user cannot free or change the data while user_buffer_in_use is set.
> >>>>>> I didn't consider the user replacing it with a new buffer. But at any
> >>>>>> rate, if that should be allowed, things get more complicated. I'll need
> >>>>>> to add a flag or something to indicate each user-supplied buffer. I'll
> >>>>>> work on it.
> >>>>> i think the API is too complex already and i dont see why it is so
> >>>>> if user buffer is set get_buffer() should return it or fail, if its returned
> >>>>> it should set user_buffer to NULL
> >>>>> calling get_buffer() a second time if user_buffer was set should be disallowed
> >>>>> release_buffer should do nothing
> >>>>>
> >>>>> if we ever have decoders that dont work with this then we need a AVCodec flag
> >>>>> that indicates them. For this case get_buffer() would then ignore user_buffer
> >>>>> and avcodec_decode() would copy to the provided user_buffer if any.
> >>>>> (we do not need this currently though because we do not have such a decoder)
> >>>>>
> >>>>> maybe iam missing something but this seems simpler
> >>>> Ok I did it a different way. New patch attached. I'm not 100% sure
> >>>> about the way reget_buffer() is handled but it works. AVFrame.type
> >>>> seems to be a mask, but I don't know if it was intended to be used that way.
> >>>>
> >>>> Cheers,
> >>>> Justin
> >>>>
> >>>>
> >>>> doc/APIchanges | 9 ++
> >>>> libavcodec/avcodec.h | 100 ++++++++++++++++++++++++++++++--
> >>>> libavcodec/pcm.c | 41 +++++++++++--
> >>>> libavcodec/utils.c | 157 ++++++++++++++++++++++++++++++++++++++++++++-------
> >>>> 4 files changed, 275 insertions(+), 32 deletions(-)
> >>>> 39eb7fb791089c0822e3f87d3226b49131563a72 avcodec_decode_audio4.patch
> >>>> diff --git a/doc/APIchanges b/doc/APIchanges
> >>>> index 4155d32..a39d9fd 100644
> >>>> --- a/doc/APIchanges
> >>>> +++ b/doc/APIchanges
> >>>> @@ -13,6 +13,15 @@ libavutil: 2009-03-08
> >>>>
> >>>> API changes, most recent first:
> >>>>
> >>>> +2010-XX-XX - rXXXXX - lavc 52.92.0 - AVFrame and avcodec_decode_audio
> >>>> + Add nb_samples field to AVFrame.
> >>>> + Add user_buffer, user_buffer_size, and user_buffer_in_use fields to AVCodecContext.
> >>>> + Deprecate AVCODEC_MAX_AUDIO_FRAME_SIZE.
> >>>> + Deprecate avcodec_decode_audio3() in favor of avcodec_decode_audio4().
> >>>> + avcodec_decode_audio4() writes output samples to an AVFrame, which gives the
> >>>> + audio decoders the ability to use get/release/reget_buffer() to get an
> >>>> + output buffer.
> >>>> +
> >>>> 2010-10-10 - r25441 - lavfi 1.49.0 - AVFilterLink.time_base
> >>>> Add time_base field to AVFilterLink.
> >>>>
> >>>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> >>>> index 4bddbaa..1aa1c8c 100644
> >>>> --- a/libavcodec/avcodec.h
> >>>> +++ b/libavcodec/avcodec.h
> >>>> @@ -31,7 +31,7 @@
> >>>> #include "libavutil/cpu.h"
> >>>>
> >>>> #define LIBAVCODEC_VERSION_MAJOR 52
> >>>> -#define LIBAVCODEC_VERSION_MINOR 92
> >>>> +#define LIBAVCODEC_VERSION_MINOR 93
> >>>> #define LIBAVCODEC_VERSION_MICRO 0
> >>>>
> >>>> #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> >>>> @@ -467,8 +467,10 @@ enum SampleFormat {
> >>>> CH_FRONT_LEFT_OF_CENTER|CH_FRONT_RIGHT_OF_CENTER)
> >>>> #define CH_LAYOUT_STEREO_DOWNMIX (CH_STEREO_LEFT|CH_STEREO_RIGHT)
> >>>>
> >>>> +#if FF_API_AUDIO_OLD
> >>>> /* in bytes */
> >>>> #define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio
> >>>> +#endif
> >>>>
> >>>> /**
> >>>> * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
> >>>> @@ -988,7 +990,13 @@ typedef struct AVPanScan{
> >>>> * - decoding: Set by libavcodec\
> >>>> */\
> >>>> void *hwaccel_picture_private;\
> >>>> -
> >>>> +\
> >>>> + /**\
> >>>> + * number of audio samples (per channel) described by this frame\
> >>>> + * - encoding: Set by user.\
> >>>> + * - decoding: Set by libavcodec.\
> >>>> + */\
> >>>> + int nb_samples;\
> >>>>
> >>>> #define FF_QSCALE_TYPE_MPEG1 0
> >>>> #define FF_QSCALE_TYPE_MPEG2 1
> >>>> @@ -2744,6 +2752,33 @@ typedef struct AVCodecContext {
> >>>> * - decoding: unused
> >>>> */
> >>>> int lpc_passes;
> >>>> +
> >>>> + /**
> >>>> + * User-allocated audio decoder output buffer & buffer size
> >>>> + * If user_buffer is non-NULL and is large enough,
> >>>> + * avcodec_default_get_buffer() may user it as an internal buffer instead
> >>>> + * of allocating its own. This only works with decoders that support
> >>>> + * CODEC_CAP_DR1. If the decoder uses this buffer, it will set the value
> >>>> + * to NULL.
> >>>> + *
> >>>> + * @note The user may not use this field when using avcodec_decode_audio3()
> >>>> + * or avcodec_decode_audio2().
> >>> I dont see why we need such special casing. *samples could be passed in the new
> >>> api like it is in the old
> >> The old API already has the samples buffer passed directly. Why should
> >> the old API be changed to accept user_buffer as an alternative to
> >> *samples? Do they have to match? If not, which takes priority? This
> >> would require added documentation to an old API. That seems more
> >> complexity than necessary when the ability to supply a direct buffer is
> >> already there.
> >
> > you misunderstand
> > why is the new api having it passed over AVCodecContext and the old over an
> > function argument (in the sense why dont you change the new api to also take
> > a argument for that?) maybe i miss something but this seems to be simpler
>
> Ah, thanks for clarifying.
>
> The new API doesn't need it. The old API needs it in order to avoid
> memcpy. In the new API, if the user wants a direct buffer, she can
> override get/release_buffer().
she can but that is more code and work
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
There will always be a question for which you do not know the correct awnser.
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